This vehicle was a corridor carriage, with 4 Second Class compartments and a brake compartment, and was built specifically for use on the boat trains between London (Liverpool Street) and Harwich. The history of class distinctions on British railways is long and complex (at one point on the Edinburgh & Glasgow Railway extended to five classes, one of which was "parliamentary"). However by the time that this coach was built, most railways provided First and Third class accommodation only, representing a major social levelling and effectively a large improvement to the travelling conditions of most passengers. However three classes were retained on continental boat trains until 1956.
But in fact, this vehicle retains nothing of its Second Class origins. The railways often re-used old carriages as "departmental" vehicles. Breakdown trains always included one or two old but usable carriages to carry the tools and materials needed at the site of a derailment, and a gang of crane drivers, fitters and labourers. This coach was transferred to Scotland and in the 1950s was converted into a Running Van for the Breakdown Train based at Grangemouth. As were most breakdown train vans, 62515 is painted bright red.