Class 35 (Beyer Peacock 1,700 hp Type 3 Diesel-Hydraulic) Hymek

After building hundreds of Type 1s and 2s diesel locomotives (with power ratings below 1, 500 hp), British Rail saw that it needed a more powerful set of Type 3 locos (in the 1, 500 to 1, 999hp range) to bridge the gap between the smaller locomotives (which often needed to double header) and the large Type 4 locomotives in it's fleet. The Class 35 was the Western Region diesel-hydraulic version of the Type 3s which began to fill out the BR fleet in the mid-1960s. It was seen as the true diesel replacement for types like the famous GWR Hall class of mixed-traffic locomotives [1].

D7029 at Kidderminster Town

Information
Number built:	101
Built:	1961-64
Builder:	Beyer Peacock (Hymek)
Engine:	Maybach MD870 diesel
Power:	1, 700 hp (1, 270 kW)
Power:	B-B

The Class 35s, which became known as the Hymek - a name derived from the Mekydro hydraulic transmission it used - were true examples of BR's second generation of diesel locomotive with as much effort being taken in the exterior design as well as the interior. The design had input from Ted Wilkes [2] who also advised on the Class 47 hence the similarity in their cab front look [3].

The Class 35 served throughout the Western Region and proved versatile locomotives, however they suffered with problems with the hydraulic transmission early on which led to the fleet requiring modifications until they could reach acceptable levels of service [4]. After these modifications they quickly became amongst the most popular and reliable diesel-hydraulic locomotives with the Class 52 Westerns [5].

Unfortunately for the Class 35 by the late 1960s British Rail's Western Region was ending its experiment with diesel-hydraulics and withdrawals of the Hymeks began in the late 1960s. By the mid-1970s the Class 35 had been withdrawn from revenue service [6]. Four have been preserved.

D7076 at Kidderminster Town

D7029 alongside the sole surviving Class 17 D8568

D7079 lurks in Kidderminster Town yard

Another view of D7029

[1] Brian Haresnape, Western Region Diesel-Hydraulics (Ian Allan, 1982) p. 52
[2] John Jennison & Tony Sheffield, Diesel Hydraulics in the 1960s and 1970s (Ian Allan, 2014) p. 12
[3] Haresnape p. 11
[4] Colin J. Marsden (ed.), Modern Locomotives Illustrated No. 212 April-May 2015 (Class 35 'Hymek') p. 11
[5] Michael Welch, Diesels on the Western (Capital Transport, 2013) p. 68
[6] Jennison & Sheffield p. 88