|Dieselisation in Great Britain|
After World War Two, the countryís railways were in a sorry state. The RAF had helped defend the skies of the Kingdom, and as a consequence, the railway network, and had crippled the continental rail system. While it did not have to completely rebuild like the systems across the English Channel, it had suffered greatly through lack of resources and overwork. The railways had been called on to move troops, supplies and munitions on top of their regular passengers and freight. Despite the extra traffic and longer trains, the railways did not receive as much money as the Government took a large part of the earnings. Steel and other materials were prioritised for war use, and the companies lost many men to war service. This meant that maintenance suffered. Despite this, the steam locomotives of the Big Four companies played a vital part in helping win World War II.
The newly nationalised British Railways was faced with competition from road network. Road haulage was becoming increasingly popular and the private car was becoming more affordable for the average family. It was becoming increasingly obvious that steam traction was outdated and something new was needed.
The choice of traction boiled down to three alternatives, diesel, electric or building more steam locomotives.
- Steam was tried and tested
- Steam locomotives were cheap to build
- Large steam locomotives were lighter than equivalent diesel locomotives of the same size because they carried their fuel in a tender. This meant that the weight was spread across a lot of axels, causing less stress on the rails.
- The railway had a huge existing infrastructure to deal with steam construction and maintenance and had thousands of skilled mechanics and drivers
- Recent developments in steam power meant that steam power could be as efficient as internal combustion.
- Because their fuel and water pulled behind them, tender engines actually could pull more when they were low on fuel. Tank engines on the other hand suffered because they lost traction as the weight available for traction was reduced.
- Steam power was noisy, smelly and dirty.
- To keep running a national system using pre-Victorian technology was embarrassing.
- Steam locomotives could not run 24-7, and they had to be kept with a light fire even when they were not being used.
- Steam locomotives need a large maintenance crew and lots of checks and cleaning both before and after use.
- A locomotiveís traction comes from the weight over the powered wheels. Tender steam locomotives kept their fuel and water in a tender, which didnít provide weight over the driving wheels. Most steam engines, especially those designed for faster services had small support wheels to allow higher speeds or larger boilers and fireboxes. These also meant that less weight was available for traction.
- Steam locomotives generate most of their pulling power at very low revs, which combined with normally less than half their weight available for traction meant they were very prone to slipping when starting.
- Driving and maintaining a steam locomotive was hard and dirty work, there were many more opportunities in the post war world for people who wanted a job, so it was more difficult to attract drivers.
- It was dangerous to run most tender engines backwards at speed because of reduced visibility, so turntables and turning triangles were needed across the network
- Steam locomotive performance depended greatly on the quality of the coal, which varied across the country.
- Diesel power didnít need a huge investment in new infrastructure.
- Diesel locomotives could be turned on and off when needed instead.
- Diesel locomotives could run 24-7 if needed.
- Diesel locomotives could be driven either way around without visibility problems.
- Diesel power was much more useful than steam for low power units like railcars and multiple units
- A diesel locomotive carried its fuel onboard so had greater weight for traction. A Diesel shunter could carry a few weeks of fuel onboard.
- Most diesel locomotives had all their wheels available for traction, which combined with the greater control that their transmissions offered, meant that they did not slip on starting and could accelerate a lot better.
- The better acceleration and without the need to stop for water, coal or to change engines, journey times could be increased.
- Diesel shunters had proved a success where they had been tried.
- Internal combustion was more efficient than regular steam.
- Diesel locomotives just needed to carry around their fuel, and not many tons of water as well.
- One diesel locomotive could replace a couple of steam locomotives.
- Diesel locomotives were easier to drive, and while they often had a second man in the cab, he did not have anywhere near as hard a task as a steam fireman. The cab of a diesel locomotive would have been a much more comfortable place to work, as befitted the second half of the 20th century.
- Diesel locomotives needed less maintenance and didnít have the long checklists of oiling and cleaning before and after use.
- A new fleet of diesel locomotives could be an advert for Great British engineering.
- Less chance of lineside fires from sparks and hot ash thrown off by steam engines.
- Diesel power was still dirty, still noisy and still pretty smelly.
- Aside from shunters, some light railcars and a few experimental locomotives, it was an untried technology.
- Diesel locomotives were much more complicated and more expensive than steam.
- One of the largest workforces in the country could need completely retraining to be able to build, maintain and run diesel locomotives.
- Diesel locomotives were heavier than steam locomotives of equivalent power and had their weight spread over less wheels, meaning that the track and trackbed would have to be strengthened for larger locomotives.
- Nobody had designed a diesel locomotive that was as powerful as the largest steam express locomotives.
- Most passenger carriages were steam heated, so additional boilers would be needed in locomotives to be able to heat the coaches.
- Diesel freezes at -9oC, a temperature not unheard of in British winters.
- Electric power was clean as all the dirty power generation came from power stations situated away from towns and stations. They were also quieter and less smelly.
- Electric locomotives were simpler than diesel and steam locomotives and had a lot less moving parts.
- Electric locomotives could be driven from either end.
- All the weight of the locomotives was over the driven wheels and because of the gradual way power could be applied, they were not prone to slipping.
- Electric locomotives were lighter than diesels or steam of equivalent power, so track strengthening wasnít needed.
- Electric power could be useful with lighter workings, such as multiple units.
- Electric trains had been successfully running suburban services for decades in the North West and South London, not to mention on the London Underground.
- The Infrastructure for electric traction was extremely expensive. Not only did the new third rail or overhead cabling1 be put in place, but also methods of power generation.
- A number of different systems were already in use in different parts of the country, and most were incompatible with each other. Some used a third rail system, some a forth rail system, others had overhead wires. Some used Alternating (AC) current, others used DC. There was also a range of voltages used.
- While a diesel or steam train could work anywhere, an electric train was confined to lines where it could get power. This would mean that rerouting a train due to an accident or engineering works would be difficult.
Managers and experts looked over all the options and came to a conclusion. The best way forward was by mass electrification. However, in post war Britain, the railways were losing favour fast. It was forgotten that the railways had played a vital part in winning the war, and now they faced massive competition from the roads. The road haulage lobby had more swing with the government and more people than ever owned private vehicles. The railways could not afford to introduce electric traction across the system in one big sweep. It was estimated that it would take until the 1980s to electrify all the main lines.
As a temporary measure, they decided to build a new fleet of steam locomotives. 999 British Rail Steam Standards would be constructed to supplement the existing locomotive fleet while lines were being electrified. These locomotives were to be cheap to build, and for steam locomotives, easy to maintain and to run. Construction of these started in 1951 and ended in 1960.
1 Overhead cabling would require many bridges to be altered.
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