British Rail Class 21 facts for kids
Quick facts for kids North British Type 2 diesel-electricBritish Railways Class 21 |
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| Power type | Diesel-electric |
|---|---|
| Builder | North British Locomotive Company |
| Build date | 1958–1960 |
| Total production | 58 |
| Configuration | Bo-Bo |
| UIC classification | Bo'Bo' |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) |
| Wheel diameter | 3 ft 7 in (1.092 m) |
| Minimum curve | 3.5 chains (70 m) |
| Wheelbase | 37 ft 0 in (11.28 m) |
| Length | 51 ft 6 in (15.70 m) |
| Width | 8 ft 8 in (2.64 m) |
| Height | 12 ft 8 in (3.86 m) |
| Locomotive weight | 72.50 long tons (73.7 t) |
| Fuel capacity | 460 imp gal (2,100 L; 550 US gal) |
| Prime mover | MAN L12V18/21S |
| Traction motors | GEC WT440, 4 off |
| Transmission | DC generator, DC traction motors |
| Multiple working | D6100–D6137: ● Red circle D6138–D6157: ★ Blue star |
| Top speed | 75 mph (121 km/h) |
| Power output | Engine: 1,000 hp (746 kW) or 1,100 hp (820 kW) |
| Tractive effort | Maximum: 45,000 lbf (200.2 kN) |
| Train heating | Spanner 1,500 pounds (680 kg) per hour Steam generator |
| Locomotive brakeforce | 50 long tons-force (500 kN) |
| Train brakes | Vacuum |
| Career | British Railways |
| Number | D6100–D6157 |
| Axle load class | Route availability 6 (5 from 1969) |
| Retired | 1967–1968 |
| Disposition | 20 rebuilt to class 29, remainder scrapped |
The British Rail Class 21 was a type of diesel locomotive used by British Railways. These powerful trains were built between 1958 and 1960 by the North British Locomotive Company in Glasgow, Scotland. They were originally known as the North British Type 2 diesel-electric locomotives.
It's important to know that the name "Class 21" was used again starting in 2007 for newer Vossloh G1206 locomotives. This article is about the original trains from the 1950s and 60s.
Contents
What is a Diesel-Electric Locomotive?
A diesel-electric locomotive is a special type of train. It uses a diesel engine to power an electric generator. This generator then makes electricity, which powers electric motors connected to the wheels. So, it's like a hybrid car, but for trains! This design helps the train move smoothly and powerfully.
Building the Class 21 Locomotives
The North British Locomotive Company built 58 of these Class 21 trains. They were made to help modernize the railway system in Britain. At the time, British Railways was moving away from steam trains and bringing in more diesel and electric locomotives.
Engine Power
Each Class 21 locomotive had a powerful MAN L12V18/21S engine. This engine could produce either 1,000 or 1,100 horsepower. That's a lot of power, similar to many sports cars combined! This power allowed the trains to pull heavy loads and travel at a good speed.
Top Speed and Weight
These locomotives could reach a top speed of about 75 miles per hour (121 km/h). They weighed around 72.5 tons, which is quite heavy, showing how sturdy they were built.
What Were They Used For?
The Class 21 locomotives were mainly used for pulling freight trains and sometimes passenger trains on different railway lines. They were important for moving goods and people across the country.
Challenges and Changes
Unfortunately, the Class 21 locomotives faced some problems. Their engines were not always reliable, and they needed a lot of maintenance. Because of these issues, British Railways decided to make changes.
Rebuilding into Class 29
Some of the Class 21 locomotives were rebuilt to try and fix their problems. Twenty of them were changed into a new type of locomotive called the British Rail Class 29. This involved replacing their original engines with different ones.
Retirement of the Class 21s
Most of the original Class 21 locomotives were retired from service quite early, between 1967 and 1968. The ones that weren't rebuilt into Class 29s were eventually scrapped, meaning they were taken apart for their materials.
Legacy of the Class 21
Even though the Class 21s had a short working life, they were an important part of British railway history. They showed the challenges of introducing new technology and how railways adapted to improve their services.
