Many of the new diesel locomotives that British Railways ordered to replace steam were either useful for tasks that were no longer needed or simply useless, yet the solution to the need for a flexible, adaptable, light freight locomotive already existed.

While such white elephants as Class 17 (1962-65) and Class 14 (1964-65) were devised, ordered, constructed and found wanting, the first batch of 128 English Electric Type 1 locomotives, later designated Class 20, had been built between 1957 and 1962.

They conformed to the misguided thinking of the time, ironically – a design based on the American switcher, rated at 1,000hp with a maximum speed of 75mph, lacking a train-heating boiler and so unsuitable for passenger trains except in hot weather.

The cab filled one end, and much of the locomotive frame was given to a long bonnet which concealed the single English Electric power unit, its weight providing adhesion for hauling heavy loads.

By the mid-1960s British Rail were lumbered with various patterns of unsuitable locomotives as the need for light freight locomotives declined, and the Class 20 proved adaptable to a range of purposes.

Crucially, they were capable of operating as multiple units – two or three locos driven from one cab – so they could handle heavier loads without increasing crew costs.

Marshalling them in pairs nose to nose provided the driver with maximum visibility of the road ahead in either direction.

Some even appeared on passenger trains, in tandem with other classes fitted with heating boilers.

Indeed, in 1966 BR ordered another hundred Class 20s to replace the ragbag designs that had to be junked quickly.

They lasted well, and turned up in unexpected places, such as the construction phases of the Channel Tunnel and High Speed One.  Of the original 228, 39 are still in existence.

They have proved popular with the leasing companies that supplement current operators’ traction needs, such as Direct Rail Services and Harry Needle Railroad Company (HNRC).

And they are usefully employed on heritage railways. Known to enthusiasts as “Choppers” because their exhaust resembles a helicopter, their noise is instantly recognisable, redolent of a particular period of British railway history, shortly after the demise of steam.

Apart from the profligate construction of untried and untested designs, the other problem with British Railways’ hastily ordered diesel fleet in the 1950s was the failure to visualise the changes that were about to overtake the transport industry.

When the order went out to replace steam locomotives with diesel, the British Railways Board ordered one-for-one replacements.

There seems to have been little appreciation that the growth of road transport and the government’s huge post-war investment in motorways would inevitably rebalance the opportunities for railways to make money into and beyond the 1960s.

So there was no long-term need to replace hundreds of small steam shunting engines with a diesel equivalent, and many of these new locomotives lay idle in store or were scrapped without being much used, whether or not their designs had proved fit for purpose.

British Railways Class 14, built at the BR works at Swindon (1964-65), was an attempt to construct a light shunter with better visibility than the steam locomotives it was intended to replace.

Twenty-six were ordered initially in 1963, followed by a further thirty before the first actual locomotive was completed.

Like the ubiquitous and highly successful 08 family of shunters, Class 14 had steam-locomotive driving wheels and connecting rods to provide adhesion and stability, but they were underpowered for some of the tasks that were available to them.

They were withdrawn from service from 1970 onwards, not because of design deficiencies but because the work for which they were intended – shunting single-wagon loads, pick-up goods trains and short-distance freight – disappeared in a very short time.

Unlike the lamentable Claytons, the Class 14 found a ready market among industrial users, particularly collieries, where many of them worked for twice or three times the length of time they were in the BR fleet.

Latterly, they have proved popular on heritage railways, where they are adept at hauling light passenger trains at relatively low speeds. Of the 56 locomotives built, nineteen still exist in preservation and another five have been exported.

Once when I was a teenager, out for a bike ride with my mates, I stopped to take a picture of the formerly triangular Ambergate Station, where the former Midland Railway main lines from Derby to Manchester and Sheffield bifurcated.

Decades later, I showed this image to an evening-class group in Matlock and, while the nice old ladies listened patiently, the rail enthusiasts in the audience began to make ecstatic noises.

It turned out that the locomotive in the picture was a considerable rarity.

Even I could see it was non-standard, painted in red ochre, with a centre cab and long bonnets concealing the engines.

This was an example of British Railways Class 17, known colloquially as “Claytons” after their manufacturer, one of a number of pilot designs commissioned after the decision was taken to replace steam traction with diesel under the 1955 Modernisation Plan.

The Claytons were a notorious result of indecisive and confused planning, undue haste to deliver untested innovatory designs, and the sheer stupidity of ordering off-plan without waiting for a prototype to be completed.

Built by Clayton Engineering Company and Beyer, Peacock & Company between 1962 and 1965, the design was an attempt to devise a single-cab locomotive with adequate visibility for the driver.  It failed.

Earlier prototypes had followed the pattern of the American “switcher” shunter, with a cab at one end behind a single large power unit.  Like the steam locomotives they replaced, which traditionally placed the cab behind the boiler and firebox, they gave the crew a limited view of the road ahead.

Providing adequate sight-lines from the Claytons’ single central cab necessitated twin power units, low enough for the driver to see past them, and these were inadequate and unreliable.  Indeed, the sightlines were still unsatisfactory because the length of the bonnets masked the track immediately ahead of the front buffers.

Some of the later deliveries of Class 17 were immediately withdrawn from the active list and stored.

After the last of 117 Class 17 locos had been delivered in 1965, the first withdrawals took place in 1968, and by 1971 they were all scrapped except one, D8568, which was sold for industrial use and is now based at the Chinnor & Princes Risborough Railway, Oxfordshire, where it operates from time to time.