BR Bo-Bo Hymek Diesel Hydraulic  7017
"A rather unkempt 7017 running light engine through Reading General station in June 1972. This engine is now preserved on the West Somerset Railway."
Photo © Michael Taylor, viewable at Railfan Europe. Thanks to John Williamson for helping trace this particular picture.

The "Hymek" B-B Class 35 diesel-hydraulic of 1961 (named after its Stone-Maybach Mekydro transmission unit) was the last loco to be part of the Western Region’s bold experiment with hydraulic transmission systems, which included the famous "Warship" and "Western" classes; even after nationalisation, the independent spirit of the GWR’s Swindon workshops continued. However, the hydraulic units were shelved due to a policy of diesel-electric standardization. Four Hymeks are preserved from an original build of 101.

From Tony Grigg's notes on "The Island of Sodor":
Number D3 "Bear"
Bear is a BR Bo-Bo Hymek Diesel Hydraulic originally numbered D7101 which arrived on Sodor in 1967. Bear is used on mainline services on Sodor and based at Tidmouth

Martin adds:
Note that as Donald and Douglas, Bear's number 7101 is one ahead of the official Hymek number sequence which ended at 7100.

Bear (D7101) arrived in "Enterprising Engines" (1968).

Modeller's Corner:   Collector's Corner:
Hornby model of Bear/D7101 available from (click image) Classic ERTL model of Bear/D7101
Hornby model of Bear/D7101 Classic ERTL model of Bear