The V2s, introduced some years before, were large and heavy locomotives, with very limited route availability.

The first engine, 3401 Bantam Cock, had a scaled-down version of the Gresley Pacific boiler with a grate area of 28.5 sq ft.[1] Its tractive effort of 27,000 lbs was produced by boiler pressure of 250 psi and three cylinders of 15-inch diameter.

The second locomotive, 3402, incorporated a fully welded steel firebox and a single thermic syphon for water circulation.

At the A1 Steam Locomotive Trust Silver Jubilee Convention, it was announced that after the completion of no.

[3] There are already parts for the V4 at Darlington Locomotive Works, including a complete set of tyres (originally made for a group in the 1990s who planned to build a V4), a chimney, and the speedometer drives from a British Rail Class 08.