Class 47 (Brush/Sulzer 2,580hp Type 4 Diesel-Electric)

The Class 47 is the largest single class of mainline diesel locomotive built for British railways with a total of five hundred and twelve built in the 1960s [1]. They became the standard Type 4 diesel locomotive and have operated on all parts of British railways on passenger, freight and engineering services. Most have now been withdrawn but there are still around thirty in mainline service plus others in preservation. Thirty-three have also been rebuilt and re-engined as Class 57s.

Number built: 512
Built: 1962-68
Builder: Brush / BR Crewe
Motor: Sulzer 12LDA28-C diesel
Power: 2, 580 hp (1, 920 kW)
Wheel arrangement: Co-Co

The Class 47 was built to allow British Railways to finally withdraw steam traction on mainline services by 1968 and became the definitive second generation diesel locomotive for BR.

Originally they were a follow-on from the Class 45/46 Peaks and indeed the first twenty Class 47s replaced the last twenty Class 46s on order [2] with some of the equipment used (and in subsequent locomotives) was chosen because it was left over from the "Peak" production. The Class 47 had an uprated version of the Sulzer 12LDA28 powerplant but with a flat front as mandated by British Rail and took advantage of improvements in technology especially in terms of weight savings to be a Co-Co not a 1Co-Co1.

There were some teething problems as might be expected with such a big class, the Sulzer diesels needed to be derated to 2, 580hp to reduce wear and tear on the engine, but the Class 47 soon became the mainstay of heavy duty services. Five locomotives were fitted with the Sulzer V12 12LVA24 engine and classified as Class 48 though were later converted back into "normal" Class 47s.

Sub-class Details
47/0 Original with train steam heating boilers
47/3 Dedicated freight locos with no train heating
47/4 Fitted with electric train heating
47/6 Single loco fitted with Rushton 16RK3CT engine testing for later Class 56
47/7 Fitted for push-pull services 
47/8 Fitted with extra fuel tanks
47/9 47/6 loco later fitted with engine to test for Class 58 

Surviving Class 47s are still used on a variety of services such as charters, spot-hires and engineering services. Over thirty have been preserved to date many in working order. One Class 47 has even worked charters in Hungary. When the class was being built in the 1960s few would have suspected that might happen! [3]
47 580 at Crewe

47 712 at Kidderminster Town

ROG 47 813 at Derby

47 773 at Tyseley

West Coast 47 237 at Tyseley

GBRf 47 749 at Kidderminster Town

[1] Colin J Marsden, Traction Recognition (Ian Allan, 2011) p. 40
[2] Brian Haresnape, Production Diesel-Electrics Types 4 and 5 (2nd Edition) (Ian Allan, 1984) p. 52
[3] "47 375 named Falcon", Railways Illustrated No.166 (December 2016) p. 10