Although the class 755A 4-14-4 was never officially meant to be built, the temptation to try it was strong. Gorote's team decided in the event to exploit the extra length to accommodate larger driving wheels, resulting in the twelve-coupled design shown here. Since the weight calculation of the 755A gave an axle load of 23.8 tonnes, it was felt that one axle less would not be acceptable and so a six-wheeled rear bogie was applied. This required a reduction in the depth of the firebox. Curve negotiation is no greater challenge than with the 655A. The design team also increased the coal capacity of the tender and fitted two six-wheeled bogies. The rest of the locomotive is of time-honoured design, including five-cylinder triple-expansion compound drive, bar frames, bokpok wheels, intermediate-pressure resuperheat and gas producer combustion system. A total of thirty locomotives were delivered in 2004 and 2005. As expected, the performance surpassed that of the 655A, owing to the larger driving wheels. A further consequence of this feature has been that the 655Bs are used on the northern plains, taking over trains which have been hauled across the mountains by the 655As. These superb engines are allocated mainly to Kalmorska, Forihv and Magane sheds.

Text and graphics © Norman Clubb 2012