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Repair time standards for transit vehicles
h [electronic resource] :
b final report /
submitted by Grisselle Centano.
[Tampa, Fla.] :
National Center for Transit Research, University of South Florida, Center for Urban Transportation Research,
1 online resource (various pagings) :
"September 24, 2002."
"FDOT project BC137-RPW032."
"CUTR account 2117-473-LO."
Includes bibliographical references.
Description based on print version record.
x Maintenance and repair
University of South Florida.
Center for Urban Transportation Research.
National Center for Transit Research (U.S.)
i Print version:
t Repair time standards for transit vehicles.
[Tampa, Fla.] : National Center for Transit Research, University of South Florida, Center for Urban Transportation Research, 
Center for Urban Transportation Research Publications [USF].
y USF ONLINE ACCESS
. REPAIR TIME STANDARDS F'CR TRANSIT VEHICLES F"INAL REPORT SEPTEMBER 24, 2002 . Submitted by: Grisselle Centeno, Ph. D. lndustiral and Management Systems Engineering Department University of South Aorida FOOT Project BC137-RPW032 CUTR Account 2117-473-LO
' REPAIR TIME STANDARDS FOR TRANSIT VEHICLES Final Report September 241 2002 Submitted by: G rlsselle C e nteno, Ph.D. Industrial and Management Systems Engineering Department University of South Florida FDOT Proj ect BC137-RPW032 CUTR account 2117-473LO 1
ABSTRACT This report summarizes the main findings and activities of the first phase of the Repair Time Standard project for Transit Vehicles. A team of two faculty from the Center of Urban Transportation Research (CUTR), one faculty from the Industrial and Management Systems Engineering Department (IMSE), two graduate students and one undergraduate student from IMSE conducted an analysis of the brake system procedure in three different locations: Lynx -Orlando, Palm Tran -West Palm and Hartline Tampa. The study was conducted from September 2001 to August 2002. This report describes in detail the procedure followed by the maintenance technicians for changing the brakes of the buses. Ideas and recommendations for Improvement are also provided. Acknowledgements Special thanks go to all the technicians across the locations that participated in this study, the in-site coordinators: Ricky Sonny, Peter Spencer and Bill Slover, and to Robert Westbrook for initiating and supporting this effort. Usa Staes, Co-PI Ed Bart, Facilities Coordinator PROJECT TEAM Dr. Grisselle Centeno, PI Vlkramadltya Bhide, System Analyst Rajesh Chaudhary, System Analyst Yasmin Palacio, Process Analyst 2
6.0 7.0 TABLE OF CONTENT INTRODUCTION A N D SCOPE ......... ......... .............................. ................ 4 BRAKE SYsrEM DESCRIPTION ............................ ............ .. .... .. ................ 4 THE TIME STUDY . ........................................... .......... .. ... ......... 5 N umber Of Obse,rvations .... ... ... .............. ..... ........ ..... 6 Data Collection ............... ......... ...... ..... ...... .. ..... .. .... .. ... ... .... ... : ....... 6 Technldan Perfollllance Rating ..................... ... ... ..... ............................... .... 7 Allowances ...... ..... ... ...... ..... ............... ............................................ ..... ... 8 ESTABUSHING TIME STANDARDS ..................... ........... ...................... 9 Benefits of tile Time Standards ................ ... ..... .... .. .. .... .......... .. .. ............... 10 Current Method vs. Proposed Method ........................................ .. .... .......... 12 Quality Assessment ..... ... ...... ... ...... ....... .......... .. .................... ........ ..... .. ... 13 DATABASE ...................................... ..... . .. ... ......... .. ... ... ... ... ... .... .. ..... ...... .... 13 E-R Diagram ................................ .... .... .... ..... ..... ... .... .. .... .. .... .. ..... . ........ 13 Requir ements .... ... ..... ... ........... ....................................... .. .......... .. ..... ..... 14 Reports ..... ....... ... .... .... .... .............. ............. ....... : ....................... ... ... ...... lS Work Flow .. ...... ... ...... ....... ... ....... ................................. ..... ... ... ...... 15 Work Log .......... ...................................................... ................... ..... 15 BIBUOGRAPHY ....... ...... ......... .... .............. ... .... ... . ... .... .. .... .. ... .... .... .... .. 18 APPENDIX 1 APPENDIX 2 CUrrent Flow Process ChartRear Brakes . ...... ........................ Al-1 Current Row Process Chart Front Brakes ........... .... .... ........... AZ-1 APPENDIX 3 Proposed Flow Process Chart ........ ............................................ .A3-1 APPENDIX 4 "Recommended Set-up .................. ............. : ......................... .. .... .A4-1 3
1.0 INTRODUCTION AND SCOPE Today, most U.S. businesses and industries are, by necessity, restructu ring themselves in order to operate more effectively in an increasingly competitive world. The public service sector is not an exception. Fundamental tools required to increase p roductivity include : methods, time study standards and work design. This study incorpo rates principles of industrial engineering and work measur ement to establish time standards for transit vehicles. Time standards define the time necessary for a qualified worker, working at a pace ordinarily used, under capable supervision, and experiencing nonmal fatigue and delays, to do a defined amount of work fo llowing the prescribed method. According to t he literature, for o rganizat ions that operate w ithout standards a 60% perfonmance is typical. When time standards are established, performance improves to an average of 85%, a 42% increase (Niebel, Fre ivalds, 1999). Establishing time standards is a step in the systematic development of new work-centers and the Improvements in metho ds used In existing wori<-centers. Areas such as planning, control, training, and scheduling are closely related to standards functions. To operate effectively, all of these areas depend on t ime and operational procedures The objective of this study is to establish accurate repair time standards for transit vehicles i n Aor ida public transit systems. This project d eve lops standards in o rde r to minim ize the time required to perform tasks, continually improve reliability of services and to conserve resources and minimum costs by specifying direct/indirect materia ls of tools to provide repair service. This report has been organized as follows: Section two describes the b rake system and the processes Involved In completing a brake job. In section three the Time Study method is descr ibed and considerations while conducting the Time Study are provided. How the standards were established Is described in section four The database development and i ts descript ion are presented in section five. Finally, recommendations and conclusions drawn from the research and a loo k into future possibilities for the Transit Sector are given in section six. 2.0 BRAKE SYSTEM DESCRIPTION During the exploratory phase of this project the steering committee, comprised of members of the Florida Maintenance Training Advisory Committee, guided the Time Standard Team to start the analysis with th e Brake System. Three locations were invi ted to participate in the study. These facilities were: Lynx in Orlando, Palm Tran In West Palm, and Hartline in Tampa. A descrip t ion of the components related to the brake system is s hown in Table 1. 4
Table 1: Description of Participating Centers LynxOrlando Hartline Tampa Total number of active 245 196 buses Average number of brake 1obs per month 46 g Active Brake 68 2 Technicians Total Brake Technicians 74 8 The Brake System Operation was divided into 10 p rocesses: bus arrangement, the removal of the tire, axel, hub and drum, disassembl y of the shoe brake, shoe mounting, hub and drum mounting, axle mounting, bus adjustment and tire mounting. For the sequence of the process see Figure 1. Flgure 1: Brake Processes For ease of data collection, these processes were divided into groups of motions known as elements. Before this was done, the analysts watched the technicians for several cycles. The total number of elements is around 260. Elements Include: remove wheel nuts, remove the outer tire move tire at side, tool set up, etc. Refer to Appendix 1 for a complete list of elements. 3.0 THE TIME STUDY Before a valid time study could be conducted four fundamental requirements were addressed. Arst, because of the many interests and reactions assodated with the time study, it fs essential that there be tuff understanding between the supervisor, employee, and time study analyst This project was strongly supported by supervisors, maintenance directors and employees. Everyone was informed of the purpose of the study and the analysts were always welcomed to the facilities. 5
Second, the analyst should be honest, patient and enthusiastic. He/she should ensure that the correct method Is being used and should accurately record the times taken. The analysts that partidpated in this study possessed these qualifications. As a result, a good relationship was established between the analysts and both the technicians and supervisors. Third, the technidans must be thoroughly aa,uainted with the processes. All the technicians that agreed to participate h_ad vast experience doing brake jobs. Although some variability existed regarding the elements, the sequence and completion of each process was very similar. Fourth, the technldans should assist the analyst in breaking the job down into elements, and work at a steady normal pace. Technidans assisted the analysts while dividing the job into elements. Most of the technicians worked at a normal pace while being observed, however, since time study directly affects the pocketbooks of workers it was evident that some were technicians worked below nonnal. Observations were adjusted with a performance factor in order to standardize the data. 3.1 Number Of ObseJVatlons Detennining how many cycles to study to conduct statistical methods were used. Since time study Is a sampling procedure, averages of samples ( x) drawn from a normal distribution of observations are distributed normally about the population mean ( f.J ). The following fonnula was used to detennine the number of cycles to observe: n = (stah"')' =(1131.44*4.303)' = 10 6048 = 11 kx 0.1*14950.3 a 90% confident level (1 a} was used an a 10% probability of error(/() The mean (x} and standard deviation (s} used were obtained from' the 4 readings taken. The total number of cycles required for the 260 elements was computed to be 10.6 observations. To ensure the required confidence, it was rounded up to 11. 3.2 Data Collection A summary of the first seven observations taken at Lynx is shown in Table 2. The eleven observations were taken as follows: Lynx-9 observations (Rear Brakes} Hartline1 observation (Rear Brakes} Palmtran2 observations (Front Brakes} While collecting the data the following inconsistendes were observed: 1. Element differences: although every technician followed the same process to complete the brake job, each technidan had a unique method of working on the elements of each process. For example, a technician will remove the tire and the axel for one side of the bus and then for the other side. Another technician preferred to remove both tires first and then the axels. Due to these variations 6
the collection of data was more dlffirul t than having a standardized process. However, it allowed us to i d e ntifying a combinat ion of best practices from the various styles. Our study recommends a standard process that is based on all the best pract ices observed and the minimum time required. 2. Facility Layout: Each participating facility had a different work-floor layout; hence travel times varied significantly depending on the layout. Thus, when we designed the new protesses, only time taken for actual work elements was considered, and allowances were provided for travel times. This makes the standards independen t of the fac ility, yet effective. 3. Equipment: Equipment used by the different facilities varied slightly. For example, one facility used forklifts to transport new hub and drums to the mechanic and take away the old ones. It was observed that this considerably saved travel time wherein the mechanic had to take the old ones to the rework bay and retum with the new one using a trolley. Table 2: Summary of Observations Time for the Work Elements Observations (Minutes) Average #1 #2 #3 #4 #5 #6 #7 Bus arrangement 6.17 5.30 6 52 5.00 5.67 4.90 7.42 5.85 lire removal 33 .03 17.25 24.45 22.03 11.00 15.22 16.73 19.96 Axel removal 29.43 28.17 19.92 15.17 13.73 11.63 20.12 19.74 Hub and D ru m removal 15' .23 34.33 36.28 28.17 15.83 19.23 15.63 23.53 Shoe brake d lsassemblv 45.40 32.18 24.12 28 33 34.87 28.10 43.07 33.72 Shoe brake mounting 43.33 49.95 29.87 30.42 85.38 45.72 44.28 46.99 Hub a n d Drum mounting 27.45 4 4.35 33 .5 2 30.00 30.o2 42.37 28.63 33.76 Axle mounting 32.97 30.37 19.58 16 .83 21.25 32.45 32.85 26.61 Bus arrangement 3.58 6.50 3.42 4.17 4.50 5.78 4.67 4.66 lire mounting 19.73 15 .0 0 30.12 18 33 20.58 25.58 20.32 21.38 Total lime (minutes) 256.33 263.4 227.78 198.45 242.83 230.98 233.72 236.2143 Total lime (hours) 4.2722 4.39 3.7964 3.3075 4.0472 3.8497 3.8953 3.936905 3.3 Technician Performance Rating The skill and effort of the technician will directly Impact the actual time required to perform each element of the study. When different technicians are observed a variability factor is introduced. Even when the same technician is observed, performance might vary fro m time to time For that reason, it will be necessary to adjust upwards to normal the time of the g ood technician and the time of the poor techn ic ian downwards Since most of the technicians always followed the same pace from beginning to end, it is customary to apply one rat ing to the entire study. Therefore, the analyst assigned a fair and impartial performance rating to each study. In the performance rating the observer 7
evaluates the technidan's effectiveness in terms of a normal technician performing the same task. For example I f a technician performs below normal a performance rate of 90% to 95% will be assigned to that technician. If the technician works much faster than normal then a 105% to 110% will be assigned. 3.4 All.owances Due to the Interruptions that can take place on a daily basis, no technician can maintain an average pace every minute of the working day. There are three classes of interruptions for which extra time must be provided. These are: personal interruptions such as going for a drink or to the restroom; fatigue which can affect even the strongest individual and unavoidable delays such as supervisor interruptions or tool breakage. The main purpose of the allowances is to add enough tim e to the normal operation time to enable the average worker to meet the established standards when performing at normal rate. These allowances are meant to give flexibility and justified rest to the technician and thus ensure smooth and efficient working. The total allowance assigned for this study is 15%. Justification to this allowance follows. Type of Percent added Allowance to Normal Time Personal 5 Basic Fatigue 4 Standing 2 Intermittent loud 2 Noise Tediousness 2 TOTAL 15% 1. Personal 'Allowance: This Includes those cessations In work necessary for maintaining the general well being of the employee. 2. Basic Fatigue Allowance: The basic fatigue allowance i s a constant to account for the energy expended to carry out the work and to reduce monotony. 3. Standing Allowance: This allowance generally accounts for the energy utilized In standing and gives flexibility and rest to the technician for standing continuously. 4. Intermittent Loud Sound Allowance: This allowance generally accounts for the sound made by the equipments used. For Instance the noise made by the air gun. 5. Tediousness Allowance: This allowance is generally applied to elements that Involve repeated use of certain parts of the body. NOTE: The allowances established may vary depending upon the wor1
4.0 ESTABUSHING TIME STANDARDS Setting llme Standards involves two complementary procedures: operation analysis and work measurement. Operation analysis is the primary technique for reducing the work Involved ; It studies all productive and nonproductive elements of an operation, and ensures the elimination of unnecessary movement on the part of material or operatives and substitution of good methods fo r poor ones. Work measurement is conoerned with investigation, reduction and subsequently eliminat ion of Ineffective time, which is time during which no effective work Is being performed Before the standards were establlshed, an extensive and thorough analysis and review of each element vvas conducted. Elements were classified Into five categories: D \I Operation Transport Inspections Delays Storage The current prooess has approximately a tota l of 260 e lements. From these a total of 156 elements were classified as operations, 60 elements were classified as transport, 12 inspections, and on average 16 delays per brake job. The complete flow p rocess chart of the current method is shown in Appendix 1. It Is Important to mention that a couple of readings for the front brakes where collected at Pal mTran in West Pal m We have seen that the repair of the front brake takes lesser time than that of the Rear Brake. The e lements i n the front brakes are merely a subset of the rear brake. For Instance, the front brakes do not have the axle removal prooess as they do not have the axle a .ssembl y in the front wheels. The flow prooess chart of the current process for front brakes can be seen in the Appendix 2. After eval uating the actual process elements were reduoed from 260 to 241. Refer to Appendix 3 for the flow process chart and time standards for the proposed method. In the proposed method a total of 201 elements are operations. Only a total of 36 elements are classified as transport, which reduces the original transport by nearly 30%. Inspections were reduoed from 13 to 4. Delays, which constituted nearly 10% of the totiJI time, were eliminated. Elimination of the delays was possible because most of them were caused by missing essenti a l s tools required to perfo r m the brake job. Due to a recommendation fo r a setup of tools before beginning the brake system job the delays were eliminated. The tota l proposed time to complete each brake job is of 2.98 hours. This is 30 % less than what the current P.rocess takes. The time reduction i s j u stified by following reasons: 9
1. All the processes and e lements are standardized that eliminates redundant operations and other inconsistencies. 2. The travel time Is reduced due to division of the complete braking system into processes and then following each process in a sequence. 3. The frequency of the equipment set u p is reduced causing reduction in the delays It is also important to emphasize that the time standards developed are realistic and feasible. This is supported by: 1. Actual readings: The standards are developed using actual data for the time required to complete work elements and tasks. 2. Normal pace: All the time suggested Is to be performed at normal working pace, I.e., with no speed increment. 3. Processes: The standard times' are reduced because of alterations made to processes, instead of changing the work tasks themselves. 4. Worker habits: Worker habit changes, like speaking to colleagues or conferring with others while borrowing tools, have been reduced by a l tering the processes i.e., making them interact less frequently Otherwise, work and basic processes of the jobs have not been altered. So, the workers will not have a problem migrating to the standards. 5. Facility layout: All the standards are based on flexible facility design, with no changes to it. Thus these standards can be implemented widely and effectively. 6. Other considerations: The approach used gives the time that is actually taken by the technicians to do the job, i.e., times are not based on the theoretic study. These are the actual time taken by the technician to do the brake job. 4.1 Benefits of the Time standards Establishing repair time standards for transit vehicles will be beneficial for: Evaluating actual performance and productivity -It provides a basis to compare actual vs. the planned use of resources. For example, If a time standard for axle removal should take half hour, and it takes one hour, then productivity will decrease and cost will increase. Determining the need for training-standards are based on the performance of a qualified worker, so management will be able to train employees to acquire the necessary skills to meet the established standard through periodic company-wide training programs. Balandng the work among the crew-standards will allow determining the optimum numoer of workers required completing an operation, It will also help to coordinate the allocation of tasks and assignment of jobs. Consequently, workforce utilization will Increase, and unaccounted time and redundancy will decrease. 10
Comparing methodsstandards are set based on good methods performed in a efficient manner, so It allows to determine if actual practices need to be Improved or modified. Scheduling -standards allow the allocation of workers for single activities and determines which personnel are available to perform unscheduled repairs or maintenance backlog. In addition, standards provide managers a better understanding of where and how all the resources are applied. Assessing the need for labor and equipment requirements -when an operation is performed repetitive ly, tile cost visibility provided by labor standards permits detailed cost evaluation and control that can result in significant savings to the company. For example, when standards are used for repair activities for the braking system, a supervisor can review the progress of a mechanic to determine whether more time, personne l or equipment is needed for the repair action. Also, If we consider specific operations such as shoe cutting, and since the work elements are known, we can allocate a worker who is more experienced in that area in stead trying somebody who m ay take longer time to complete the task Establishing preventive maintenance activities -most preventive maintena nce (PM) activities invo l ve routine systems, component and mechanism checks. The majority of these activities, when broken down Into their elements, correspond to the elements of standards developed for production and repair activities and may be used for establishing best processes for PM. Benchmarking-this is a popular tool for assessing financial and operational efficiencies of an organization. In benchmarking, the processes of the organization conducting the study are compared with another facility. In such a scenario, operational Time Standards provide a very good parameter for comparison. 11
4.2 Current Method vs. Proposed Method A general compari son between the current m ethod and the recommended/proposed method is shown In Table 3. Table 3: Current vs. Pronosed M e thod Current m ethod Proposed Wheel removal Two metllods exists: lire removal method (diSaSsembly of 1. Wheel removal method (removing entire wheet each tire at the woridng area) assembly and transporting it to the rework bay) 2. lire removal method (disassembly of each tir e at the worklna area\ Set up There Is a con siderable amount of The set up time Is reduoed as t h e set up time required due to the use operation Is carried out at the of the overhead crane wori
4.3 Quality Assessment One of the oonoems of the managers Is the quality assessment of the job performed following the proposed time standards. As mentioned earlier, time standards have been established considering that the technician will be working at a normal paoe. However, several ideas to address this conoem are listed next. Job sampling: To conduct sampling of the jobs is a supervised inspection of various jobs selected at random. Due to the nature of the jobs, number of jobs sampled should be around one In five. Ideally, every job would have to be checked for quality, although this task would involve additional labor and time. Certification program: Another way to reduoe "comebacks" Is by making a certification program, wherein a checklist is made for every job type, and the vehicle overall, to check functionality and quality. The overall bus certification would indicate the health of the machine, and workers can use the system dlecklists after they finish working on every job. This would mean the same worker can assure all quality norms specified in the checklist, and supervisors can do sampling less frequently. The database could also be configured to track "comebacks" without much difficulty. It would store information about all the buses and jobs performed on them, and every time a comeback occurs, an entry would be made using interactive forms. This would allow a manager at any given time view the comebacks at a glance, and identify further training/problem areas to ensure better work quality. 5.0 DATABASE A database that provides information on the time standards for the repair of the braking systems has been developed. The database shows the work elements required to do the repair jobs on the transit vehicles along with the standard time required to do the job. It Is intended to help the managers to evaluate the relative productivity or the combined productivity of all employees. In addition, it allows managers to schedule specific tasks to employees and to obtain an estimate of ending time of those tasks according to the standards previously determined. A Users' Manual was developed to help a layman learn to understand and operate the database with ease, and generate customized reports for viewing, please refer to it for more details. 5.1 E-R Diagram All the tables within the database are connected to one another In some way, such that the data can be viewed using the reports In any manner. The relationships are shown In the Entity -Relationship Diagram (Rgure 2). Explanation of each table is covered In the data dictionary. 13
Figure 2: E R Diagram 5.2 Requirements To use the Transit database, minimum system requirements are: Intel Pentium processor, AMD Duron or equivalent (500 MHz system speed) 64MB RAM At least 50 MB of free hard disk space (8 GB HOD preferred) Microsoft Office 2000, Professional edition. Microsoft Windows 2000 operating system CD ROM (16x preferred) 14
5.3 Reports Three reports can be generated by the database: the Work Flow Report, the Work Log Report and the Performance Level Report. A description of each report is provided in the following sections. 5.3.1 Work Flow As shown In Figure 3, this report shows at a glance the processes involved in a brake job, their standard times and a brief description of the processes. This can be handed to a worker along with the flow chart proVided with the database to use as a guideline. The Management can also add/edit processes through the forms, and all changes will automatically be reflected In the Reports. Figure 3: Work Flow Report IIIIIIIUIUIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIJIIIIIIII11.11111111111liiiiiiiiiiiiiiJIIIIIIIIIIIUIIIIIIIIJIIIIUIIII WorkFlow IIIIIIIIIIIIIIIIUIIIIIIIIIIIIIIII UIIIIIIIU IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIILIIIIIIIIIIUIIIIIIIIU System Name brakes Procem H ame S:td Time M i nutes 0 -ucrlpUon Attangem onl 6 R a i se b u s and b;;u;k up br;.tko; Gfand T ot
Fig ure 4: Woti< Log R eport ... .............. ,................. .. .. .. ......................... ....................... .. ............... . ... .. ... ........ ..... Work Log .. ............. ,. .................................... .. ............. ................ .. ........... ........... ... ....... . ............... _,_ , First bst N otn e Job Type Std Tl.me Operator Tlmo -FiiJ---ctia.:;ahary--------------.. ---.. --.. 300 32 8/29/D)2 bt::ikU :;oo 333 713 1 12002 brskes 300 340 1m12002 b1<1kes 300 :l66 7/3112002 bnlk&S :;oo 763 91112002 Vik El'lide b rskas 300 410 811212002 bna:kes 300 295 8112/xtl2 brakes 300 340 8f12/XJJ2 300 245 8/1 21.a:tl2 300 30 9/1 512002 5.3.3 Performance Level: This Is a graphical report (Figure 5) and shows a t a g lance the number of jobs worked on, and the average performance level for the jobs. Thi s will allow management to find out the preparedness o f the facility to do brake jobs. Fig ure 5 : Perform a n c e Level Rep ort Performance L evel lm>kes Syste m For more details related t o the database please refer to the Database User's Manual 1 6
6.0 CONCLUSIONS AND RECOMMENDATIONS At the conclusion of this phase, a wealth of infonnatlon has been compiled and documented regarding the brake system. A critical review of the numerous observations and a thorough analysis of the data have been conducted. A database system has been developed and requirements necessary to support this service have been described. Tests of recommended procedures are still being validated. Although the recommended procedure has been tested once, the tota l time recorded was 2 hours and 59 minutes. This time included three small b reaks o f nearly 8 minutes each. The prindpal finding of the work to date is that the establishment of accurate and consistent standards improves execution of the procedures required to complete a brake job. We expect to extend this study to other systems such as transmission, a/c, etc. with the guidance of the advisory committee and the support of FOOT. In examining the brake process from a top-down or systematic perspective, the Time Standar d Team Identified several common problems that are best characterized as: Lack of consistent and accurate procedures among technicians and facilities. Lack of proper set up. Lack of proper arrangement of tools and parts. The primary recommendation is the implementation of the standards and process suggested by this study are shown in Appendix 3. Some recommendations were also provided In section 4 (Current vs. Proposed Method). Further recommendations follow: 1. Sequential workflow: Each process specified should be fin ished completely before starting the next process. Working on two processes simultaneously may affect the efficiency of both. For instance, while removing the left side wheel, it is more time-efficient to set up the air gun and remove both wheels on the left side and then move to the other side. 2. Forklifts: An arrangement can be made to transport the new shoe brake and hub & drum assembly to the working place and the o l d ones back to the rework bay using a forklift operated by an additional technician for about 2 minutes, there would be considerable reduction in the total job time. Approximately 12 15 minutes were allocated to this task during the time study. 3. Set up times: The set up should be done before starting the job. That is, the required tools should be procured and kept handy for the brake job before the work order is obtained and time for job is measured. This includes air guns, tool trolley, tire dolly, cleaning bath, trolleys and all other required tools. Also, procurement of all parts that need to be replaced according to FDOT/USDOT specifications must be done when the work order is taken so it is not necessary to visit the materials station frequently. This considerably reduces travel time. Refer to Appendix 4, the recommended setup. 4. Ergonomic Position: It is recommended that while working on the brake Job, the bus should be lifted up to waist-hei ght. It has been observed that this position is most convenient and puts the least strain on the back, as the worker has to bend less. This a lso enhances work efficiency. 5 Lighting: The shop floor should be well lit, especially during the evening shift, so that the use of flashlights by mechanics is minimized. 17
7.0 BIBUOGRAPHY Barnes, R.M. Motion, and Time Study: Design and Measurement of Worts, Wiley, John & sons, Inc. New York: 1980. Haemisch, G.C. and Miller, F.G. Increasing Productivity in Bus Maintenance Functions, Proceedings AIIE Spring Conference, 1976. Haghani A. and Shafani Y. Bus maintenance systems and maintenance scheduling: model formulation solutions, Transportation Research Part A-36. 2001 \ Inaba, K. NCTRP Synthesis of Transit Practice 4: Allocation of Time for Transit Bus Maintenance Functions, TRB, National Research Council, Washington, D. C., 1984. Martin-Vega L. SPT, Data Analysis, and a Bit of Common Sense in Bus Maintenance Operations: A Case Study, AilE Transactions, 1981. Maze T.H and Cook A. R. Theol)' and Practice of Transit Bus Maintenance Performance Measurement, Transportation Research Record 1140. TRB, National Research Council, Washington, D. C., 1987. Nlebel B. & Freivalds A., Methods Standards & Work Desjgn Time Study Boston: WCB McGraw Hill. 1999. 18
. t"IIRI 1=1 n w QQ nT DESCRIPTION: of the trans i t . OPERATION TIME SUMMARY NO MINUTES 177 156 tj 55 60 12 7 : 0 :.AYS 16 22 \7 0 0 '" 260 245 i'iME ITS II i (Sec .) . BUS !ll'lll n of the bus on the lifter 240 : for the c D 'V 45 ,;,.o:J the 30 : for backin g c 11 D \1 30 o o" on the jack c:::>DD\1 25 AXLE /Al '\. t>et tool big) ( ) .. D D \1 150 pet tool '\Smau J () J D \1 66 air gun (too l ) o .-.oov 60 ToOl set up for the air gun c:JDD\1 45 axl e nuts (* 10) c:JDD\1 30 nuts(* g) MOD\! 18 1 Idle time Q c:: I \J 180 IRE o w ... o:J lock and pins (manual) D D \1 30 Idle time 180 A1-1
WORK (Sec.) on glasses and collecting 120 25 pins tools TIRE REMOVAL A1-2
: . WORK ELEMENTS TiME (Sec.) 0 ____ Q 0 D \7 10 nut I o JD\l 15 Fra:.:..:::._ver _____ -----'----+1 tj J D \l 20 c::JOD\7 M Get the hydraulic lifter Q -::.. O D \7 Pi'aCfri9 : lifter to remove ""'" q 0 0 \7 15 assembly O 0 0 \7 30 jM, .. DYE.v!tithiee Wiieei't0ti1 to thiee! sSiiiide ) If 0 0 \l 20 'the "'"'gum.: lifter to the v
(Sec.) 30 60 30 Al-4
WORK (Sec.) nuts nut mechanically SHOE BRAKE DISASSEMBLY arrangement lin ing A1
air gun to remove sprays side) preparation to remove grease on A1-6 TIME (Sec.) 60 120
grease on lhe shoe liner grease SHOE BRAKE MOUtmNG SIDE nut assembly A1-7 TIME (Sec.) 60
WORK ELEMENTS procurement () .. 0 D '\} +ie;;j,tg;-;:rea;;;;se;;,. :;fro00m;t;re;;tw;aork;;;;bidaruy O D \7 grease on hub and vu" c:) O D '\} !""'' grease o n wheel axle cj O D \7 fefett'Qgire:reaasise!t.! rro:omrme;o;:kibiaYav-----1(, 0 0 \1 ....... grease on hub and drum assembly c:) O D '\} TIME (Sec.) 120 120 40 15 120 45 .,..,..,, grease o n I axle r 0 0 \1 35 jJe time '-C:::: 1 .'---V"---li----:-: 6 = 0 --l "',,. floor area [ D '\} 120 :Jean axl e axle accessories (ball '91 c:j 0 D '\l 120 ; (ball GOD\1 12o vuu axl e seal and bush c:> 0 D '\l 10 ovum seal ..... G 0 D '\l 1 5 FP'Y grease c:j 0 D '\} ..... )If 0 D '\} vvu axle seal and bush r side) c:j D \J ouuu c:j 0 D '\] t f'f''r grease [j D \J 15 90 1 0 20 15 .. .. tui ball .. q 0 \1 5 littiii9" "?' nut v c:j 0 D '\} 30 the hydraulic tool and move to other s ide J 0 \1 60 fo1,vve .. ,.Jaiidiii andl .rut ball bearing q D '\} s ""' nut ln uall q 0 D '\} 27 the andm--ov-::-e-;:it:. ) -..._ r D '\l so time ( ) q =-._'---\JY-...l'---140---' / A1-8
.. -. -r-] TIME (Sec.) OYI MOUNTING axle head 1 axle head 1uuocr side) !die time tire OU;JO \' IIJ IC) .0 ) \1 35 IT WIIM MOl 11 ""' / IJt cJ  ) \1 25 _0 ) \7-40 fill air bags to raise the bus over the to the ,. 0 D \1 l the bus idle time I ( C::: 1 L \1 130 t;Ou;;t;;,ig,,.jandt ,Of [ J ) \7 66 ld__O ) \1 30 c:J o n \7 18
(Sec.) the nut mechanically nut cap the and torquing the bearing device time cap brakes 35 A1-10
WORK ELEMENTS '"e = 4.08 HOURS A1-11 TIME (Sec .)
bus Brakes tools and set nuts A2-1
w ith SHOE BRAKE 1\J.-2
TIME old in slot Break HUB AND DRUM
nut & washer and out nuts A2-4
" DESCRIPTION: Braking System of the transit vehide DESCRIPTION:Repair time for the braking systems TOTAL SUMMARY NO. O 201 36 TIME 155 24 ; [ 4 1 1-::: ____ -+ : v 0 0 WORK ELEMENTS TIME BUS Ann .. the bus on the !!!!!.== lift=-er ___ 45---1 91 ILEFTSIOE AirGun l Q 0 D V ITool set uo I Air Gun ) l D V 57 ;:..!.... cr *=ton.;__ ____ _._,:....._.._ Q-=--0-=D--"---LV-=---st__, I A3-1
WORK ELEM E NTS the nuts A3 z 0 ... 0 z ... l2 .. 5 ... Q TIME 30
W O R K E LEMENTS axle seal and t he A 3 z .... D. 0 z 3; z .... j .... c TIME
WORK ELEMENTS TIME drum lifter BRAKE shoe A3-4
WORK ELEMENTS and and a i r anchor and dowel Include A3 z 0 s z 6 w ... !2 ... TIME
z z 0 w f 6 5 1:> WORK E LEMENTS Ill TIME z w w ... :2 ... Q ... Ill z 0 ... .. th e hammer and an a n d air A3 6
WORK ELEMENTS TIME the seal on the 123 A3-7
WORK ELEMENTS hub and drum A3-8 z z ... nME
WORK ELEMENTS axle and ham m e r to fit axle nut A3-9 z 0 ... ... 0 z 0 ... Q II) i5 TIME 4 6
WORK ELEMENTS A 3-10 z 0 w c. 0 z 6 w e; z TIME ..
z z 0 6 w 0 > ... :s WORK ELEMENTS Ill TIME z w w ... w i2 Ill Q ... z 0 ... .. 65 23 STANDARD TIME A3
Appendix4 Recommended Set-up
SET UP REQUIRED FOR THE TlME STUDY 1. The arrangement of the tool and the new parts that needs to be replaced by as per the specification of FOOT is to be done before starting the repair of the system. a. The tools include the air gun, dowel pin plfers, sledge hammer, wiper seal tightening equipment: . b. The new parts include the wheel nuts, lug nuts, lock washers, dowel pins, axle seals, gaskets, axle nuts, wiper seals, shoe brake nuts, beatings, and other things depending on the replacement required. 2. The shoe lining should be assembled. The standard does mit include the time required for cutting the shoe lining and assembling it. 3. The drum should be cut: and set so as to be replacing the old one. 4. The lifting equipment be located near the working area . A4-1