Voidships

A Steampunk History of a World at War

The Atmospheric Railway

 
nimda
nimda's picture
Monday, 25 October 1847

Isambard Kingdom Brunel demonstrates his sealed tube "atmospheric railway" with carriages partially levitated using Faraday's Principle and pneumatic power pushing them along at speeds of over 88 miles an hour.

Background

The actual atmospheric railway as developed by Victorian engineers can be read about [Bad Link: Plugin Not Found] however this is not the system that Brunel developed in the Voidships universe.

What we have is more like [Bad Link: Plugin Not Found] where the complete train runs in a tube. At intervals there are pumping and generating stations (it's cheaper to maintain static pumping and generating stations than individual mobile trains) pushing air under pressure into the tube which drives the levitating train at speeds of up to 150mph (reached in 1890).

Riding on air

The atmospheric railway trains do have a driver, he has some control over the speed of the vehicle through the multiple seals around the front carriage (head) of the train. This carriage has a series of seals which hold back the pressurised air, the tighter the seal the more the train responds to the pressure. By releasing the seals the driver can control the speed. His other option is rather dramatic but he can switch off the levitation. In order to maintain the gravity nullification throughout the train it must still use electrical power, the train head contains a Tesla converter taking broadcast power from the Tesla generators in the pumping stations.

At the beginning and up to the mid-1880s the carriages were not themselves pressurised and could be quite uncomfortable since the pressure would steadily fall and then suddenly rise when the train passed a pumping station. As speeds, and therefore pressures, increased it became necessary to pressurise the passenger compartments, though they were never perfect. (Apart from Her Majesty's Atmospheric Railway carriages.)

One important feature of the atmospheric railway is that inclines barely affect them. With a strong pumping station at the bottom of a hill, or even mountain, the train will power up any slope with barely diminished velocity.

The ubiquitous nature of the atmospheric railway means that all trains are called "tubes" colloquially. (In the real world, the use of "tube" for the London Underground only came about when the Central Line was opened and advertised as the "Penny Tube".)

Underground

In London the entire underground system is composed of atmospheric trains, their routes marked by the pumping stations. Unlike the mainline routes where trains can be extracted sideways from the tube, or run-off into a side track running alongside the platform, the tube trains stop with their doors lined up with doors in the tube itself which open at the same time. (The approach used on today's Jubilee line at some stations.)

The door seals on the underground are not perfect and tend to suck air in as the train approaches (there is low pressure in front of the train)

Manchester

Manchester did not follow the route of London and used high-level tubes instead. This is largely due to the cost, the fact the Manchester is quite a bit smaller than London and because the developers had a free reign, unlike in London.

Construction

The atmospheric tubes are constructed from iron rings skinned on the inside with thin steel - sufficient to hold the pressure. To ensure passengers are not kept in the dark, polished quartz windows were used originally but eventually glass technology developed sufficiently to create thick curved panes that could fit neatly.

Atmospheric trains cannot be derailed but lines cannot cross in the same way as normal railway lines - points where tracks split are complex affairs where a whole section of wall can be rotated from. Track joins are much simpler.

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