Think of a number...
JOHN CROSSE offers a potted history of the train numbering system in the UK
Everything has to have a number - as far as computers are concerned, they don’t seem to be able to work with names. But long before our modern computers were invented, items of machinery were identified by numbers. And railway hardware was no exception.
Names sufficed in the early days, but so much stock was soon required that numbers were the only sensible way of identifying them. Somehow, numbers also appealed to those who liked collecting, particularly locomotive numbers.
Today, we have very long ‘European’ numbers allocated to our stock, although thankfully most units and locomotives carry a shortened form under the TOPS designation system. But for diesel and electric locomotives and units, these are only the latest manifestation of their identification system.
Before nationalisation in 1948, each company had their own systems. This could (and did) result in some duplication, although that was of little concern as each company both looked after and manned its own engines.
With the coming into being of British Railways in 1948, it was decided that there should be a common numbering system throughout the country, regardless of owning or operating region. Much was made of (say) having to add a ‘3’ in front for the Southern Region (and so on), but the fact that specific number series had been allocated to the few diesel and electric locomotives seemed to pass almost unmentioned - all diesel locomotives were now to be in the 1XXXX series and Electrics in the 2XXXX group.
Unlike most steam engines, which just had the additional number placed at the front, nearly all diesel and electric locomotives were completely renumbered. The size and shape of the numbers conformed to the Gill Sans standard applied to steam engines.
Under the modernisation plan of 1955 there were initially to be locomotives of types 1-4. It was thought that the existing numbering system did not have sufficient flexibility to accommodate the large number of new locomotives, where the number range would indicate the power classification of the engine, and thus the fourfigure number system with a D or E prefix to denote diesel or electric power was introduced.
Initially the large-size numbers were kept, but some renumbered shunters had a small D prefix and others a D with a full stop, before a new smaller font was introduced as a standard with white numerals rather than the steam standard of cream.
Stability reigned until 1965, when the experiments with corporate blue started which led to the introduction of a new and larger font for locomotive repaints from 1966.
The demise of steam brought about the next change. It was no longer necessary for the numbering to differentiate between steam and diesel power, so in October 1968 it was announced that the use of the D prefix would cease, although electric locomotives would continue to use the E. It appears that Brush Type 4 1712 was the first engine to emerge from Crewe works without a D.
While many locomotives lost the prefix on
repaint, a large proportion of the fleet, which retained green livery, had to have the D painted out. Some depots opted to remove the whole number and apply the new larger-size numerals. The D prefix removal took until around 1972 to complete, with a few remotely located shunters hanging on to their Ds.
Blue repaints also showed variations on the placing of both numbers and arrows, until eventually only two sets of numbers and a central arrow symbol became the norm - just in time for the TOPS renumbering to introduce yet more variety and interest.