The Rail Safety Improvement act does not specifically state

that particular equipment must be added to the locomotive.

However, to achieve success with positive train control,

there will be a need for added features to onboard

computing & communication capabilities. The locomotive

will include a new onboard computer, radio, and dedicated

PTC display initially. There may also be a need for a fourth

dedicated PTC display at the conductor's station. The

railroad back office will communicate with the dispatch

system and send information directly to the onboard

computer including items such as speed restrictions,

authorities and train data. The four primary Class I PTC railroads in North America have also standardized on a 220 MHz radio for onboard to wayside communications. All onboard lead locomotives will be 220 equipped, but not all railroads will use it as the primary communications between the onboard and the back office. Railroads may need to add other incremental items to the locomotive to have a fully functioning & interoperable PTC system. The exact requirements are in the process of being defined by the Interoperability Train Control Committee and will be made available to the industry as quickly as possible to enable efficient conversion to a PTC environment.

The locomotive onboard computer will:
1) house a track database that will receive updates from the back office
2) receive track authorities and
3) receive speed restrictions generated from the back office and then communicate in signal territory to the wayside equipment.

Routes that are cab signal equipped will interface directly with the cab signal electronics onboard the locomotive to determine signal aspect. Based on that information, the onboard computer will know where the locomotive can be and how fast it can travel, and ultimately determine if enforcement is necessary based on speed and authority. Enforcement of authority or speed is accomplished when the onboard computer applies a penalty brake application to stop the train.

Suppliers are actively working with the ITC committee to develop solutions and are targeting provisioning of locomotives for 2010.