 Class 71 and 73 are based on the Swedish X2 , built by Kalmar Verkstad ( KVAB ) for the Swedish State Railways , and introduced in 1990 . Carbody is built of stainless steel . Forty @-@ three units were delivered by 1997 ; they each considered of a locomotive and two to five unpowered carriages , including a driving trailer . The locomotives had a power output of 3 @,@ 260 kW ( 4 @,@ 370 hp ) and a top speed of 200 km / h ( 120 mph ) . Compared to X2 , Class 73 has an upgraded bogie construction and motors in multiple cars instead of having a locomotive unit . The latter forces a four @-@ car configuration , but allows for better traction and better use of space and weight by placing the technical equipment throughout all four cars . 
