Head End Power

In NARS, passenger carriages require power for heating and lighting. This power is provided by the train's locomotive, and will either increase the running cost, decrease the horsepower, or both.

Carriage Type	HP reduction	Running cost^
Passenger Car with steam heating	50hp (dynamo under car)	$350 per year
Passenger Car with HEP from traction system	100hp	$125 per year, only incurred when train is stationary
Passenger Car with HEP from seperate system	none	$700 per year
Bilevel Car with steam heating	100hp (dynamo under car)	$700 per year
Bilevel Car with HEP from traction system	200hp	$350 per year, only incurred when train is stationary
Bilevel Car with HEP from seperate system	none	$1400 per year

Steam locomotives and early diesel and electric locomotives provide steam heating (the diesels and electrics have special steam generators for heating), and electrical power for lighting is generated by dynamos under each car. Locomotives built after 1970 have HEP (Head End Power) provided by either the traction system or a seperate HEP generator. HEP provides electrical power for both heating and lighting.

The RDC, Metroliner and EMU generate their own power in each car, and so do not have any additional costs.

Diesel and electric locomotives without a steam generator or an HEP system cannot haul passenger trains.

^uninflated 1921 dollars, with vehicle running costs on medium.