Manager's Forum

How has advancement in fuel technologies changed your fleet maintenance procedures?

Fort Worth, Texas
Dick Ruddell
President/Executive Director
Fort Worth Transportation Authority (The T)

With today’s emphasis on “green” operations, more transit agencies are making the switch to alternative fueled fleets. The T began converting from diesel to compressed natural gas (CNG) in 1988 and today has more than 175 buses that have accumulated 80 million miles with reductions of approximately 1,200 tons of nitrogen oxide and 9 tons of particulate matter.

The advances in CNG fuel technology and equipment manufacturing have improved significantly since we put our first CNG bus on the road, resulting in modifications in maintenance procedures on an ongoing basis.

We have grown from two small compressors at 500 cubic feet per minute (cfm) to five large compressors capable of 3,500 cfm. This allows us to refuel the entire fleet in six hours. By using the fifth compressor as a spare, we also avoid refueling delays due to maintenance. Our expansion with more advanced compressors required the addition of in-house staff for 24/7 maintenance of our fueling service station. The improved efficiency of CNG vehicles has changed the “fill up” frequency of our buses from twice to only once in a 24-hour period.

Procedures in our shop were changed to ensure safety. We installed a system that warns of any methane or carbon monoxide leaks. Should a major leak occur, all personnel are warned to immediately leave while a signal is sent to open all doors and activate the shop ventilation system. This clears the area of gases so that emergency bus repairs may be resumed quickly. These procedures are part of the annual refresher training for all maintenance personnel.

Vehicle maintenance created the greatest changes in our procedures. The original CNG engines were proto-types that were unreliable and received constant updates from the original engine manufacturer (OEM), requiring them to perform most of our maintenance. Over a period of time, the vehicle updates resulted in the engine reliability improving significantly and because of the process The T had put in place, we were prepared to take it over.

So that The T could gradually assume the role provided by the OEMs we set up a process to have our technicians observe every step the OEM techs took in order for us to gain the knowledge and skills we needed to maintain these units. We also sent our techs to training schools and asked the OEMs to send their trainers here. Our goal was to ensure that by the time the warranty period expired on any upgraded vehicle, The T would be fully capable of maintaining its CNG engine.

The advancements in CNG technology have also affected our hiring and training practices, as we now emphasize electronics skills. As a result, The T’s maintenance team won first place for “MCI Multiplex I/O Control” at the 2009 APTA bus conference Roadeo.

We’ve also made changes to the procedures for our preventive maintenance program. Because CNG engines are clean burning, they are susceptible to overheating and causing engine failures. Should the engine parameters exceed specification, an engine could experience catastrophic failure without warning. So, we modified our program to conduct tune-ups every six months. We established checklists that outline exactly what the technician would accomplish without the option of making his own decision. This has proven significant to operating a reliable fleet.

With good maintenance processes in place for advanced CNG technology, we look forward to additional changes to accommodate 10 CNG articulated buses in 2010 that will mean modifying two work bays due to their larger size and fine-tuning bay-availability schedules.

During the early development of CNG transit technology, The T was on its own to find the experts, manufacturers and fuel specialists to help us. Today, an agency can hire a contractor with the know-how and experience to do a turnkey setup for its switch to natural gas.

The T has also initiated a new National Transit Natural Gas Coalition to pull experienced agencies and experts together to share their knowledge about natural gas fleet operations and maintenance and help those just getting started. We received great response at our inaugural meeting at the 2009 APTA annual conference, and invite anyone interested in joining to contact me at

Culver City, Calif.
Art Ida
Transportation Director
Culver CityBus

Maintenance practices have changed with the introduction of alternative fuels, as well as in conjunction with implementation of advanced transit technologies such as electronic destination signs, fareboxes, AVL-smart bus systems and other operational systems required of a modern advanced technology public transit vehicle.

Culver CityBus elected to move to compressed natural gas (CNG) in 1997, and has realized significant benefits in emissions reductions and far lower fuel costs. However, moving away from traditional diesel fuel to CNG required a complete paradigm shift in maintenance practices, facilities design and operation, CNG station maintenance, operating procedures and training. This required the following:

  • Education of maintenance and facilities staff on the practices necessary for safely maintaining and operating a gaseous fuel
  • Re-evaluating and adjusting preventative maintenance (PM) intervals, procedures and inspections
  • Increasing PM inspection times
  • Inspections of the CNG fuel system (tanks, fuel lines, fittings, PRD Valves)
  • Inspections of the methane gas detection systems
  • Inspections of the fire suppression systems
  • Inspections for leak detection during each PM cycle
  • Extending engine overhaul intervals for the cleaner-burning engines.

Technician training is one of the most important of these areas. Properly trained technical staff will prove to be paramount to the “new” maintenance objective and necessary for a successful transition. Our technicians now actually prefer to work on CNG equipment because these vehicles are technically advanced and provide them the opportunity to utilize their full complement of skill sets. They also prefer to work on CNG vehicles because these engines are far cleaner, (both internally and externally) than their diesel counterparts.

Training is also important for vehicle operators so they come to understand the different operating environment of an advanced technology bus. Most of the basic functions are seamless, but there are some unique differences which operators will need to understand.

Our staff, our elected officials and the community have completely embraced our CNG alternative fuels program. Since 2004, the Culver CityBus fleet has been 100 percent CNG-powered, and the city of Culver City operates close to 60 additional non-transit light-, medium- and heavy-duty vehicles running on CNG. Culver City looks forward to future advancements in natural gas applications to include CNG hybrid and natural gas fuel cell technologies, and if implemented, we will in turn adjust our fleet maintenance operation to accommodate these advancements.

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