ZF Produces new rail drives for Rome and Milan Metros

ZF will equip the metros built by Hitachi Rail for Italy's two largest cities of Milan and Rome with the latest generation of its two-stage spur gear drive. Compared to its predecessor, the unit is around 10 % lighter and features newly designed, noise-optimized gearing. This increases the vehicles' potential payload, saves costs and makes the ride more comfortable for passengers. ZF will produce around 1,200 drives for both fleets. The Group will present the new model and further innovations for the rail industry at Stand G60 during the Expo Ferroviaria exhibition (Milan, 3 to 5 October).

For Italy's largest metropolitan regions - around the capital Rome and the commercial center Milan - rail transport plays an important role. Several million inhabitants, not to mention the countless tourists, commute "in treno." In Rome alone, three metro lines transport over one million people every day. Hitachi Rail, which will realize the next generation of vehicles for these metro networks, will install a new two-stage spur gear drive from ZF.

Quieter, lighter, powerful

Reliability, high power density and, above all, weight savings were at the top of the list of requirements for the new rail drives. The last two rail drive generations of the Metro fleet also came from the German company. "So we knew how to go about it," says Alfred Kienzle, Team Lead for Rail Drive Systems Product Development at ZF. "That's why we were able to efficiently streamline the development of this series."

The time span between the award of the contract by the ATM Milan to Hitachi Rail and production maturity was just under 12 months. During this time, ZF developed a new, noise-improved gearing and optimized the spheroidal graphite cast iron housing. The result: at 307.5 kg (dry, without torque support and clutch), the unit weighs around 10 % less than its predecessor and also saves almost 30 % on material costs. On the other hand, robustness and durability remain unchanged - they correspond to the proven ZF standard.

Due to the reduced weight, it contributes to the reduction of vehicle weight which consequently saves energy spent in train running. The savings are significant considering that about 16 transmissions are installed for each train. In addition, the drive is quieter during operation, which increases on-board comfort. Another bonus: Thanks to the same connections, it is also possible to retrofit existing vehicles. This may save public transport companies the costly renewal of the fleet.

ZF sets the standard in the Italian rail sector

These advantages also convinced Hitachi Rail, the manufacturer of the new metro vehicles for Milan and Rome to work with ZF. Metro Milan already has 736 drives in its order book, which corresponds to 46 trains. In Rome, ZF is to equip a total of 30 trains and expects a total quantity of 480. "With this order and in view of our previous success story in the industry, one could say that we are setting the benchmark in the Italian market," summarizes Michael Topp.