MARTA's Technology Partnership

In 1994, the Metropolitan Atlanta Rapid Transit Authority (MARTA) found themselves in the middle of a technology revolution as it prepared to order its next fleet of buses. By the time it was over, MARTA would have implemented four new products simultaneously that reduced their operating expenses and maintenance costs.

It began when MARTA was looking for an alternative to its high-floor buses after the Americans with Disabilities Act was passed in 1990. One of the mandates of the law was that all buses be equipped with wheelchair lifts. However, wheelchair lifts used in high-floor buses are expensive and prone to failure because of complicated electronics, mechanics and hydraulics. So MARTA was open for a more affordable and reliable option. The low-floor bus, introduced and marketed by New Flyer Industries, Ltd., a leading supplier of buses to North American Transit, proved to be the solution for MARTA. "The time and money we spent on maintaining the wheelchair lifts on the high-floor buses are practically eliminated since we started using low-floor buses," said MARTA's Manager of Engineering and Bus Maintenance Seyed Mirsajedin. "Low-floor buses enable us to use a simple ramp that rarely needs to be repaired." According to New Flyer Marketing Manager Pam Vernaus, the low-floor bus is standard at MARTA, and the company has delivered a total of 3,000 low-floor buses since 1991.

In addition, New Flyer introduced its Allen-Bradley Programmable Logic Controller (PLC) to MARTA. New Flyer was the first OEM to employ the PLC concept of a main onboard computer that could be programmed to communicate with and control sub-systems. The PLC was installed in 51 low-floor buses, and MARTA found that the unit eliminated one-third of all wiring, connectors and relays, therefore, significantly reducing the weight of the bus.

"One of the major benefits of the PLC is that if you want to incorporate new features to the bus – like flashers when the door opens – you can easily do this without adding another wire or switch," said Mirsajedin. "The biggest problems in buses are loose connections and wire corrosion that lead to electrical malfunction. The PLC reduces the number of connectors and wires that are needed. As a result, the number of related failures decrease, which provides us with a highly reliable product."

As MARTA was developing the specifications for the 51 low-floor buses, the company decided to test two new products – the Thermo King Brushless Motors and the Thermo King IntelligAire Microprocessor Based Control System.

After a two-year reliability study, MARTA found that the brushless motor is a superior product in terms of durability and reliability. "Brushless motors last much longer than motors with brushes. And we spend less time and money maintaining the equipment, because we don't have to replace brushes on a regular basis," said Mirsajedin. "We use about 280 brushless motors per year, and in the past four years, none of them have failed or have needed to be repaired. The regular motors had to be repaired often and replaced once every two to three years.

"We save about $100 to $200 per bus, per year with brushless motors. And with less time dedicated to repairs, we save even more. Brushless enables us to increase our bus availability and provide better service for our customers," added Mirsajedin. Not surprisingly, brushless motors are now a standard at MARTA.

The IntelligAire system controls interior bus temperatures and performs diagnostic analyses on the air conditioning system. "IntelligAire is a very solid system, because there are less components that could potentially fail," said Mirsajedin. "By the nature of its design, this technology is much more reliable than the electrical switch control system we used before."

The partnership with New Flyer and Thermo King not only saved MARTA time and money, but it also made it possible for Thermo King and New Flyer to test the reliability of their products.

According to MARTA Director of Bus Maintenance Brooks McAllister, the partnership with Thermo King and New Flyer was a smart move. "We opted to implement many new technologies at once as opposed to retro fitting older models. This way, we've saved time and money," said McAllister. "When we initiated our partnership with New Flyer and Thermo King, we were in the process of ordering new buses, so the timing of introducing the new technologies was perfect."

MARTA operates 703 buses – 169 of them are low-floor buses with the Thermo King and New Flyer technologies. "As a standard practice, we retire buses after 12-14 years. We plan to eventually replace all of them with the low-floor buses, brushless motors, IntelligAire and the PLC," said McAllister. MARTA has recently been awarded 206 low-floor buses to be delivered in year 2000. By that time, the transit authority will operate 375 low-floor buses with the Thermo King and New Flyer technologies.

In October, MARTA will begin testing another Thermo King product – R407C refrigerant, a replacement for R22. MARTA will be the first North American Transit Authority to use R407C in a rearmount unit application.