I was born in the Bedfordshire village of Flitwick (it was a village then) on the Midland Main Line, so the British Rail Peak diesel locomotive was part of my childhood. I can recall sitting in the classroom at Harlington Upper School watching them perform their daily rosters, when I should have been studying hard!
For two decades this rugged design was the mainstay of express trains out of St. Pancras to the north of England. Never a star performer in the way the Deltic was, lacking the style of a Western diesel hydraulic, or the efficiency of the ubiquitous Class 47, which partnered it on the Midland Main Line, the Peaks gave sterling service for two decades until they were replaced by High Speed Trains in 1982. They served in other parts of Britain’s rail network, but they were the dominant form of motive power on the Midland Main Line, hammering through Flitwick at their maximum speed of 90mph.
The Peaks were part of British Railways 1955 Modernisation Plan, which aimed to replace steam with electric and diesel traction. This plan called for a category of mainline diesel locomotives with power outputs of 2000bhp and above, known as Type 4. Both English Electric and BR responded with similar specifications. The English Electric Type 4, later known as the Class 40, was a 2000hp locomotive introduced in 1958.
The Peaks were BR Derby’s own take on the Type 4 specification. However, both Derby and English Electric found that the heavy internal components and the need to keep within the British loading gauge, prevented them from keeping weight to an acceptable level, which forced them to use four axle bogies. This resulted in both types of locomotive weighing in at a whopping 133 tons.
The initial fleet of ten Derby-built Type 4 locomotives used a Sulzer 12LDA28-A diesel engine to drive a Crompton Parkinson GC426-A1 main generator which supplied power to six Crompton Parkinson C171-B1 traction motors. All this resulted in a 2300bhp 90mph diesel locomotive. These first ten locomotives were all named after British mountains, which resulted in all the subsequent locomotives being called Peaks by rail enthusiasts. These initial ten locomotives, numbered D1 to D10, were delivered to British Railways’ London Midland Region in the winter of 1959/60 and operated out of Euston and St. Pancras.
BR were impressed with the performance of the Peaks enough to order an uprated version with a 2500bhp Sulzer 12LDA28B engine. A further 127 of these were built between 1960 and 1962 by BR’s Derby and Crewe works.
From 1962 these 2500hp locomotives became the dominant motive power on the Midland Main Line operating out of St Pancras, ousting the LMS-era Jubilee, Royal Scots and Patriot steam locomotives. The Midland Main Line had been the ‘Cinderella’ line of the London Midland Region. Weight restrictions had prevented the use of the mighty William Stanier-designed Pacifics in order to accelerate schedules. The Royal Scots in rebuilt form were as good as it got for their size, but the Peaks transformed services out of St. Pancras.
These days trains out of St. Pancras terminate at Sheffield but, at one stage, Peaks travelled further north, to Glasgow via Carstairs Junction, and Edinburgh via the Waverley Route. Although not well patronised by Londoners, because they were longer and slower than services out of Euston and Kings Cross, they did offer convenient Anglo-Scottish services to residents of places like Leicester, Nottingham and Sheffield.
In 1961 BR Derby began building another variant of the Peak design. The 2500hp Sulzer 12LDA28B engine was used again, but differed in the fitment of a Brush generator and traction motors, in place of the Crompton Parkinson equipment. BR built a further 56 examples. However, in 1962 Brush Traction cracked the problem of producing a lighter Type 4 locomotive, resulting in the long-serving Class 47, and no more Peaks were ordered.
It was a testament to the quality of the Peaks that they remained a frontline locomotive despite the onset of more modern and lighter designs. In the late 1960s, the Peaks were progressively repainted Rail Blue with yellow ends, and a new classification scheme clarified the various sub-types.
The original ten 2300hp locomotives were re-branded as Class 44s. The next 127 2500hp machines became Class 45s and the final 56 examples with Brush components were now known as Class 46s.
The emasculation of services out of St. Pancras began in January 1969 with the closure of the Waverley Route between Carlisle and Edinburgh, which isolated vast swathes of Border country from the national rail network. The section between Galashiels and Edinburgh was resurrected in September 2015 as the Borders Railway, and hopes are high that eventually this will be extended further south.
In 1976 St. Pancras to Glasgow services also ceased. The original ten class 44s were latterly confined to freight traffic and were withdrawn between 1976 and 1981.
The arrival of the High Speed Train/InterCity 125 sounded the death knell of the Peaks. Arriving on the Western Region in October 1976, the HST initiated another game of motive power musical chairs, resulting in the final elimination of Diesel Hydraulic power from the region. The HST took over the main services out of Kings Cross in 1978. The final batch of HSTs were allocated to the Midland Main Line in 1982, and they have given even longer service than the Peaks they replaced.
The arrival of the HST freed up more modern designs like the Class 47 and the freight-only Class 56 to supplant the Peaks, and the Class 45 and 46 locomotives were withdrawn between 1981 and 1989.
An amazing 16 Peaks have been preserved. Although overshadowed by the publicity surrounding the InterCity 125, in their day the Peaks were as much a quantum leap over the steam locomotives they replaced as the later HST, particularly on routes like the Midland Main Line, where weight restrictions prevented the fastest steam locomotives from being utilised.
And so to the pictures… The first is a blue-painted Peak hustling through Flitwick, Bedfordshire in 1977 at 90mph. Then, we move back a decade to 1967 and is of green painted D22 in a snowscape, two miles south of Hawick on a now closed section of the Waverley Route.
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