The contract includes the supply of spare parts and operation and maintenance training, and an option for up to five additional locomotives, which could take the value of the contract to $US 154m. The units will be built at Siemens' plant in Sacramento, California, and are set to be delivered in early 2018.

The new fleet will replace eight ageing AEM-7 and ALP-44 locomotives on Lansdale - Doylestown, Paoli - Thorndale, and Wilmington - Newark commuter services, and will also enable Septa to increase capacity by expanding the overall size of its fleet. The ACS-64s will operate with the existing fleet of push-pull coaches, although Septa is planning to order 45 double-deck coaches to further boost capacity on its Northeast Corridor services.

"The purchase of these locomotives is the first of several new vehicle purchases which are part of Septa's Building the Future programme," says Mr Jeff Knueppel, Septa's general manager. "We are looking forward to their arrival to help provide a faster and more reliable regional rail service for our rapidly growing ridership."

Like the order from Illinois, Maryland and California for 34 diesel-electric Charger units confirmed last week, these locomotives deploy a microprocessor system to perform self-diagnosis of all key systems, make self-corrective actions and notify the driver in the event of an issue. In addition there is a redundant system to provide continuous heating, cooling, lighting and door operation to passenger coaches in the event of a failure. The locomotives also meet the latest federal rail safety regulations, including crash energy management components, and utilise regenerative braking.