The previous Class 141 rail vehicles had been criticised because they were the same width, 2,500mm, as the National and therefore failed to take advantage of the greater width available to standard gauge trains. British Rail normally works to a width of 2,815mm (9ft.3in.) which can comfortably accept 3+2 seating. The problem was that the highly tooled roofsticks could not be cut and lengthened.
An ingenious solution was found by incorporating cove pieces which effectively added half the desired extra width into each side. This the Class 142 railbuses achieved a nominal overall width of 2,800mm. At the same time the opportunity was taken to include in these cove brackets the necessary reinforcing members to meet the railway vehicle end-loading requirements.
It had been intended to offer this increased vehicle width as an option for customers who required it. In the event Alexander cut the ground from under Leyland's feet with its class 143, built jointly with Andrew Barclay & Sons of Kilmarnock, which met BR's existing width specification and Leyland was left with no choice but to offer the wider version at no extra cost for the whole of the class 142 contract - the so-called wide bodied vehicles. This decision had severe financial implications but was indicative of the area into which Leyland, with BR's assistance perhaps, had propelled itself.
