Draft:Indian locomotive class PT

The PT class (Passenger Tank) was a broad gauge tank locomotive designed to haul passenger trains on the railways in British India. It was one of the BESA locomotives developed by the British Engineering Standards Committee, later called the British Engineering Standards Association (BESA).

History
The PT class was first catalogued in the second edition of the standard from 1907. Robert Stephenson and Company built seven locomotives for the South Indian Railway (SIR) in 1936, bearing the works numbers 4114 to 4120. This batch differed significantly from the earlier F and FS classes (which correlate to the original BESA design with internal valve gear) by having outside cylinders. In service, the locomotives were used in heavy suburban traffic, and were numbered 7 to 13. Number 11 has been preserved and is on display in the National Rail Museum of India in New Delhi.

Technical aspects


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 Schmidt superheater - the S stands for superheated. In the PT series, external cylinders and Belpaire firebox 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 gear with a rotating camshaft from the Lentz system.

Weblinks

 * &#32;PT Locomotive in National Rail Museum of India in New Delhi