British Rail Diesels
The "Duff" (class 47)

This article first appeared in the May/June 2003 issue of AMRA's 'Journal'.
By 'Electron'

The class of locomotives that were to become known as the 47 class (or "Duff" as they have been nicknamed) are the largest class of diesel locomotives built for the British Rail fleet with 512 locomotives in all being built during the early 1960s. The design was basically a cross between those used by prototype diesels Falcon and Lion.

The pilot contract was signed with the Brush group of companies in February 1961 to design and construct 20 locomotives and these were allocated running numbers D1500-D1519 (these numbers had previously been allocated to an order for class 46 locomotives that had been cancelled). Construction of the first locomotive commenced at the Falcon Works in Loughborough in January 1962 and was completed by September of that year. The locomotive then commenced road trials under the control of Brush engineers and railway CM&EE officers. Most of the trials were carried out on the Midland Region but the entire 20 locomotives in this first batch were allocated to the Eastern Region. The first locomotive actually entered service in October 1962.

Prior to construction of the first batch of locomotives even commencing, a repeat order for a further 30 locomotives was placed with Brush. These locomotives would be allocated running numbers D1520 - D1549. Construction of these locomotives was identical to the first batch except that these locomotives were not fitted with electric trail heating (ETH).

Over the following three years a number of further repeat orders were placed with Brush and some final construction work was also carried out at the BR workshops at Crewe. The locomotives were initially allocated numbers D1500 through D1999 but as D2000 had already been allocated to another class (no one expected so many locomotives to be built for a single class) the final twelve locomotives to be built were allocated numbers D1100 through D1111. While numbers were allocated in the order that the orders for the locomotives were made, this did not necessarily reflect the order in which the locomotives entered service. The 512th locomotive in the class was D1961 which finally left the works in May 1968.

When originally built locomotives D1702 - D1706 were fitted with a different engine from the rest of the class. When the TOPS numbering was introduced these five locomotives were allocated to class 48 with the rest being allocated to class 47. While the engine fitted to these locomotives worked just as well as the engine fitted to the others it was non-standard and these locomotives had their engine replaced in 1971 (and a corresponding transfer to class 47). These locomotives were then given numbers 47114 through 47118.

As originally built some locomotives were fitted for steam heating, some for electric heating, and some intended for freight only use with no train heating at all. In the case of electric heating the first order of twenty locomotives provided this via generators. These were the only locomotives so fitted and subsequent locomotives to be fitted with electric heating used alternators instead.

D1938 carried out push-pull and high speed trials during the mid 1960s and also had its engine rating reduced from 2750hp to 2200hp but these experiments did not prove successful and the locomotive was restored to its original condition and use.

D1733 left the works at the time when BR was experimenting with new liveries and as a result this locomotive was painted in 'early blue' livery for use with the XP64 stock. This livery was the forerunner of the standard BR blue livery introduced a couple of years later so this locomotive was effectively the first locomotive to appear first in blue rather than green livery.

The locomotives were progressively repainted into blue livery between 1964 and the late 1970s and in some cases the locomotives were first introduced in blue livery. For a period of time the locomotives coming from Loughborough were apprearing in Blue while those from Crewe were still being painted Green. While not a common site is was possible to find a green 47 working alongside one of its blue brothers over quite a long span of years.

After several years of operation the engines in all 512 locomotives were derated from 2750hp to 2580hp without any significant loss of power for the required operations but with a greatly increased life for the various engine components.

In 1971 experiments were underway to uprate D1562. This experiment was unsuccessful with an explosion and resultant fire writing off the locomotive completely. Other locomotives were written off due to accident in the early years as well. These locomotives were D1671 ('Thor'), D1743, and D1908. The other 508 locomotives survived to be repainted and renumbered and were all still in operation in 1984.

The new TOPS numbers were added quite hurriedly to the 47 class locomotives with many having the new numbers applied without undergoing a repaint at the same time. During the renumbering period (mid 70s) many locomotives could be found with their new number proudly displayed in the middle of each side with the old number hastily painted out (sometimes with black paint) under the cab side windows.

In January 1976 one 47 class locomotive was called upon for several months to perform a very unusual duty. The locomotive (minus bogies) was used as a stationary exciter for the Central Electricity Generating Station at West Thurrock in Essex while the normal exciter at the plant was repaired. Apparently this was a cheaper option than any of the alternatives.

The introduction of TOPS numbering saw the class divided up into three sub-classes. These were originally intended to be called 47/1, 47/2, and 47/3 but by the time that numbers were actually added to the numbers the classes were renamed to 47/0, 47/3, and 47/4 respectively to more closely match the numbers actually carried by the locomotives in each class. Since that time a couple more sub-classes have been added.

Locomotives from the class were allocated to most regions and the locomotives can be found operating across all regions. The locomotives are also used for a variety of purposes so you never know quite what to expect to see next being hauled by one of these locomotives.

Since 1984 a number of the 47 class locomotives have been withdrawn from service. Some of these are due to accidents (such as the fire that wrote off 47713). Others may have just become too costly to maintain (I don't have full info on what happened in this period). In any event this was still the most numerous class of locomotives in use into the 1990s and into the privatisation period following the breakup of British Rail.

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Copyright Stephen Chapman