With the success of the first Type 4 diesels, Derby Works began the development of the next generation of even more powerful locomotives, the Class 45 and Class 46. These would go on to form the bulk of the Midland mainline fleet for many years.
Despite the 45s and 46s not being named after mountains as their Class 44 counterparts had been, many were honoured with the names of famed British Army Regiments, however, they still retained the nickname Peaks.
The Class 45 and 46s were pretty much identical to the 44s, also weighing in at around 135 tonnes and powered by a diesel power unit produced by Swiss engineering company, Sulzer. However, the newer power units produced 2500 horsepower, 200 more than their predecessor.
This led to BR placing a more substantial order of 127 locos for Class 45s, this was so many in fact, that Crewe Works were also drafted in to assist Derby with their construction.
The first BR Class 45 entered service in late 1960, with the class soon becoming the main loco to work out of St Pancras on the Midland Line services, demoting the dwindling number of steam locos to cover local services or freight.
The final variant of the Peak began production in 1961, now with Brush Electrical Equipment fitted after re-tendering for the next batch of locomotives. This tweaked peak would be known as the BR Class 46.
Externally it looked almost identical, as it had the same engine and body, however, its electrical equipment had received an upgraded generator and different traction motors. Developed by the Brush Company of Loughborough these upgrades replaced the previously used Crompton-Parkinson electrical equipment of the Class 44 and 45.
- Directional lighting.
- Next18 decoder socket.
- High-quality motor and drive mechanism for smooth running.
- NEM coupler pockets.
- Numerous separately fitted parts including handrails and wipers.
- Etched radiator fan grill.
- High quality speaker pre-fitted