Valve control with rotating Camshaft System with Lentz valve gear
The PT series was a broad gauge tank locomotive for passenger transport on the railways in British India . She is one of the BESA locomotives developed by the British Engineering Standards Committee , later called the British Engineering Standards Association (BESA). The abbreviation PT stands for Passenger Tank Locomotive.
The PT series was the tank locomotive intended for passenger transport, which was first listed in the second edition of the standard from 1907. Robert Stephenson and Company built seven locomotives for the South Indian Railway (SIR) in 1936, which had the works numbers 4114 to 4120. On the railway, the locomotives used in heavy suburban traffic were numbered 7 to 13. The number 11 has been preserved and is exhibited in the National Rail Museum of India in New Delhi.
The locomotive was listed in the BESA standard in three variants, which differed in the steam boilers used . A larger standard boiler with a diameter of 5 ft 1 1⁄4 in (1556 mm) was developed for the PT, which was also provided as a variant in the third BESA standard for the SP and SG series locomotives . Alternatively, the existing boiler from the SP and SG series could also be used, provided that the weight of the locomotive was adjusted in accordance with the requirements of the standard. The PTS variant used a boiler with a smoke tube superheater system Schmidt - the S stands for superheated .
In the PT series, external cylinders and Belpaire standing boilers were used, with the grate being arranged between the coupling wheel sets and therefore being relatively narrow. In contrast to the standard, the SIR locomotives were equipped with a valve control system with a rotating camshaft from the Lenz system . Small cow catchers were attached to the two buffer beams .
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