Friedrichshafen (Germany) / Washington (District of Columbia). ZF will produce a newly developed two-stage spur gear drive for the Washington Metropolitan Area Transit Authority (WMATA). The first units will be delivered in July 2023 and will celebrate their premiere in Hitachi Rail's new WMATA 8000 series of vehicles. Tailored to the US rail network's specific requirements from its earliest conceptual design, the new transmission is certain to impress with its high efficiency, despite the low weight, and its optimized smooth running.
Washington D.C. is a major hub of activity. This is the city where most of the important political issues of the US and the globe are decided. But many business sectors – above all in science, technology and the media – are also shaped here. As a result, the city's metropolitan area is the sixth-largest in the United States, which is reflected in the city's vast rail system, the Washington Metro. Opened in 1976, the network now includes six lines, 91 stations and around 188 kilometers of route. With an average ridership of over 220,000 people per weekday, it is only surpassed by the New York City Subway in terms of passenger trips.
Such intensive use requires technology that performs robustly and reliably. When the Washington Metropolitan Area Transit Authority (WMATA) opened up bidding for proposals for the modernization of its fleet, Hitachi Rail was awarded the contract – bringing ZF on board as a proven partner for the driveline. The result: A newly developed two-stage spur gear drive from ZF that will celebrate its premiere in July 2023, when the first train of the new WMATA 8000 series rolls out of the depot. The first order comprises in total 256 vehicles.
Optimized from the ground up to customer requirements
"We've worked intensively to develop the transmission's optimally to meet the WMATA's requirements," says Dieter Panowitz, Product Development Rail Drive Systems. The main focus was on the power-to-weight ratio. At only 310 kilograms, the new model is 80 kilograms lighter than the previous one, so that it complies with the maximum axle load of 14 tons. Though considerably "leaner", it boasts a high efficiency rate as well as low-wear and noise-optimized gearing trimmed to passenger comfort. The requirements specification attests to the famous robustness of ZF products. The system is designed for a service life of 30 years.
Other strictly American features have been taken into account as well. The spheroidal graphite cast iron housing is extra compact to save valuable installation space and designed to support the traction motor. All screw connections that need to be loosened and fastened during the servicing and maintenance of the transmissions have been selected according to the US customary measurement system in order to make on-site servicing easier. ZF has also adapted the transmission's maintenance concept to that of the vehicles. This means that the trains will have to visit the depot less frequently, which reduces the total cost of ownership.
ZF and Hitachi: A well-established team
The order from Washington D.C. is another success in the partnership between ZF and Hitachi Rail. The two companies have been cooperating in the rail sector for more than 15 years. To name some of the previous achievements in the US, both companies have won orders from the Baltimore, Miami and Honolulu public transport authorities.