0 to 60! Just how nimble are today's locos and units, and what's the quickest off the mark?

Lockdown means our performance trials are on hold, but the break offers a chance for some analysis of what we have seen so far.

SINCE this series began almost six-years ago, we have recorded 71different classes of locomotive and unit making a start from 0-60mph on the level. This has included examples of diesel and electric locos, ex-British Rail and post-BR DMUs, and AC and third-rail EMUs.

A general rule of thumb is that units are quicker off the mark than locos, electric traction faster than diesel, and AC power better than DC. This is reflected in our combined league table, which is headed by AC-powered EMUs and tailed by diesel locos. But within these broad categories are some interesting variations.

The quickest run we have recorded so far is on one of Northern’s new CAFbuilt Class 331 EMUs, which took just 35 seconds to hit 60mph from a standing start on the level. The slowest is the CFPS’ main line-certified Class 40 No. 40145, which took 325 seconds, while the median value in the series – and also coincidentally the fastest diesel loco – is a GWR Class 57 at 76 seconds.

The devil is in the detail, however, and pure times alone cannot tell the whole story as the load is an important consideration. For example, the table for diesel locomotives and HSTs shows that a 2+4 HST set was (not surprisingly) quicker than a 2+7 or 2+8 set – but Class 57 and 68 locos on roughly similar loads are not too far behind the 2+4 HST.