How the civil work of undeground rail way lines are done?

Question

How the civil work of undeground rail way lines are done?

Answer 1

In London the earlier lines built in the mid-Victorian era were built by first digging a cutting, laying the track at the base of this and then covering over. This is known  as 'cut-and-cover'.

By the beginning of the 20th century tunnelling methods had advanced and it was possible to tunnel much deeper. The tunnels have a circular profile, having been made with a circular tunneling 'shield' with the tunnel itself being lined with bricks or concrete as the shield advanced.  This is where the Underground gets its name, the Tube, although the Tube tends to be used as a generic name for all Underground lines, including the earlier ones.

The trains which run on the deeper lines have a lower roof line which is dictated by the circular profile of the tunnels.

Maintenance is carried out by teams of engineers who go to work in the early hours when the trains stop running. The power to the conductor rails is turned off and they travel on battery-powered trains which are recharged in the daytime.

About 50% of the London 'Underground' network is in fact at ground level, and some of it (like the District Line at Putney Bridge) is even above ground. It is only in central London that the lines go through tunnels.

Answer 2

Creating an underground railway is done one of two ways.

The Cut and Cover method. Or tunnelling.

Certain amounts of London underground is done via the 'cut & cover' method; whereby a large pit of where the railway is to be built is dug up, the tracks put in and associated infrastructure, then covered, where full work can be done. In London these refer to 'sub-surface' lines.

Tunneling, basically consists of either digging, manually (less likely thesedays) or mechanically, where a hole is bored underground - reference to this is best exampled by the Channel Tunnel.

Answer 3

Large scale engineering work to the London Underground network will require engineering trains as described above. However, for day-to-day maintenance most of the equipment and material will need to be carried down by the track gang themselves, particularly on the deep level tube lines. This means that lighting, trolleys, power tools, lifting gear and anything else that they might need has to be taken in and out, often along the same walkways that the public use, and down the tunnels to the work site.

This makes it a very long and labourious process to get anything much done, particularly as they have a small timeframe in which to hand back possession of the line before the trains start running, which is why LUL prefer to shut down entire sections of the line over a weekend to maximise the amount of work that can be achieved.

Answer 4

Just to add to what the first question has said, day to day civil engineering is usually done on the London Underground at night, or at weekends. It is just not practicable to shut the system down during the day for 'engineering possessions'. The power is switched off and the fleet of battery powered locos built to tube diameter are used for such things as spoli and ballast trains.. The companies working on the sub-surface lines, built to normal loading gauge have actually acquired, or hired in, main line diesel locomotives for the works of reconstruction they are engaged on.

There is a good wikipedia article, with photographs, on the battery locos and their use:- http://en.wikipedia.org/wiki/London_Unde...

There is an article on the Metronet site about its fleet of engineering trains, together with a link to more photographs:-

http://www.metronetrail.com/default.asp?...

Answer 5

If your talking about underground railway lines in Sydney, they basically do the same thing as outdoor lines, when it's men working on it, there is an orange light and  when a train is coming, the orange light turns off so the men get out of the way. I hope this helps. I'm not quite sure what you want.