The Altoona Works BP4 #999 is a type of rebuilt four-axle, 1,350hp EMD battery-powered electric locomotive (though with a diesel locomotive's body and components) built in 2009 by the Altoona Locomotive Works of Norfolk Southern. It is the only one of its kind built, though it is to be joined by 12 similiarly powered locomotives, according to Norfolk Southern's Sustainability Report.

The type is rebuilt from an EMD GP38 with replacing the existing prime mover (engine or motor) with a set of 1080 12-volt lead-acid batteries and associated control equipment. Despite appearing somewhat similar to a conventional diesel-electric locomotive (or any particular or typical modern type of North American diesel locomotive), the BP4 has no diesel engine and battery charging is provided by gaining energy from an external power source. Battery life is extended by the use of regenerative braking, which returns power to the batteries.

It was initially designed or built to demonstrate an electrically-powered locomotive's capabilities, with it being a hybrid prototype. Though, the type itself was intended to be an experimental way of conserving energy or to demonstrate battery-powered types of electric (or diesel) locomotive's capabilities for hauling freight on such railroads as Norfolk Southern. Though, the type itself is actually one of the only types of battery-powered electric locomotives ever owned or built by any North American Class 1 railroad; making the BP4 an extraordinary marvel for North American-based Class 1 railways and/or railroads.


This conversion significantly alters the external appearance of the locomotive, with the cab (which is actually brand new) being moved forward on the frame to make room for a large louvered battery box, which takes the place of the locomotive's long hood. The fuel tank is similarly replaced with another battery box.


  • The BP4 is sometimes considered unaesthetic by railfans and train enthusiasts because of its unusually "stubby" nose
  • The BP4 was designed to operate 3 shifts on a single battery charge.
  • The locomotive ihas been repowered with 864 lead-carbon batteries from Axion Power International and is currently being operated in Altoona's Rose Yard.
  • This is the only locomotive on Norfolk Southern's roster powered exclusively by electricity