The logical progression of the evolution of 753 class motor locomotives was its culmination with the manufacture of two T 478.4 (754) class locomotive prototypes with increased motor output and electrical wagon heating. Electrical heating was indispensable to be able to form trains from modern wagons that no longer had steam heating facilities. These locomotives are intended primarily for express passenger train transport on non-electrified routes. Due to the fact that the output in excess of 1325 kW can be used only for electrical heating, its traction properties are the same as for 753 class locomotives, and for heavy express trains, for example from Prague to Karlovy Vary, or to Plzen before electrification, it was necessary to run them in tandem. The prototypes were delivered in 1975, and the company didn't begin series production until 1978, after extensive testing and modifications. A large fire in the CKD Diesel Motors manufacturing plant in the summer of 1980 prematurely ended delivery however, and despite the manufacturer's and railway's efforts, production was not successfully reestablished. Two locomotives were converted into test units designated 754.201 and 202 from prototypes 754.001 and 002.
In terms of mechanics, the 754 class locomotives are practically identical to the previous 753 class locomotives. The traction assembly is composed of a K 12 V 230 DR diesel motor with heightened output of 1460 kW (1980 k) and DC traction machines – the TD 804 B traction generator and four TE 005 E traction motors. An electrical heating alternator powered mechanically via a KUBLO flexible clutch from the output flange of the traction generator is inteded for heating wagons. For the first time, the principles of a unified position were applied to the engine operator's position, and instead of a steering wheel for shifting driving stages, a lever with lateral movement and continous power regulation was used.
The locomotive body was red (cherry red), the same as the stripes, which were however trimmed with white, similarly to the window frames and headlights. The frame, undercarriage, internal window frame surfaces and all equipment on the bottom of the locomotive were dark grey, and the couplers and bumper asseblies were black.
|Original ÈSD series designation||T478.4|
|Current series designation||754|
|Number produced for ÈSD||86|
|Number in ÈD fleet||60|
|Drive wheel diameter||1000 mm|
|Bumper-to-bumper length||16540 mm|
|Continuous output||1460 kW|
|Maximum speed||100 km/h|
|Service weight||74,4 t *)|
|Number of traction assemblies||1|
|*)754.291 a 754.202||74,5 t|