Widened Lines

First of all Welcome to our little chatshow Benedict. I would agree with TOK that even if the thing were physically possible it would cost the earth moon and stars to do it.

If I understand correctly someone please explain to me how existing tunnels will be used for Crossrail I've seen two proposals and both will use running lines in new tunnels between Paddington and Liverpool Street.

An interesting story I heard about the Widened lines was when the disused Hotel curve was converted into a service diversion tunnel for the Kings Cross Project. During the works archive drawings on its construction (presumably 1860s) were examined by the engineers. These drawings showed rooms built in the tunnel walls with some unusual domed brick structures inside labelled as igloos. On the top of these igloos there were stove pipes that reached above to street level. Apparently sand was passed down these pipes and picked up by gangs of men with shovels and spread onto the rails to improve traction. The track was not only curved but also had a steep gradient. The trains of the day weren't powerful enough and really struggled to get up the curve hence the need to assist it in such a way.

The drawing specifications required that each room had to be closed off by a timber doorway of tight fit to keep out the large amounts of coke fumes generated by the locomotives working at maximum to overcome the gradient. It was said that the men would sit in these enclosed rooms waiting for the sound of an approaching train. Before the train arrived they would run out with the sand, deposit it and run back into the room, shutting the door behind them.

The existing tunnels won't be used to run Crossrail through. But the site where the Widened Lines exist (Farringdon-Moorgate) will be used for things such as Crossrail construction access, ventilation, and escalator access to the underground platforms.