On the London underground which track costs most to maintain. In tunnel or in the open?

Answer 1

I'm surprised you asked this. Tunnel tracks cost more by far. The surface tracks can be serviced by standard main line tamping machines and maintenance trains can be pulled by diesel locomotives. New class 66 locomotives have recently been delivered for that purpose, see link.
http://www.metronetrail.com/default.asp?sID=1144840875078
simply put all the techniques and tools developed for main line maintenance can be used outside.
The tunnels however don't benefit from any of that and a lot of routine maintenance tasks still have to be done by hand. Special battery electric locomotives
http://en.wikipedia.org/wiki/London_Underground_battery-electric_locomotives
have to be used on maintenance trains. The deep level "Tube" lines have an even more restrictive loading gauge then the subsurface lines. All maintenance has to be done at night in the short period the Underground is shut, about 6 hours. However It often takes 1 hour to get to and set up the appropriate equipment in central London locations and a further hour to pack up and do any safety checks, leaving about 4 hours every night to do maintenance. Also in there is dust that must be removed from the tunnels and water must be pumped out. The tunnel structure must also be maintained. A particularly difficult line to maintain is the Waterloo and city line as this has no external connection except a hole at waterloo that the rolling stock is lowered down. Recently it was found to be necessary to close the line in order to replace the track.
http://www.tfl.gov.uk/tfl/press-centre/press-releases/press-releases-content.asp?prID=881

Answer 2

I would say in the open, as it is exposed to the elements, which to me suggests more on-going maintenance would be required.

On the other hand, work in the tunnels requires more specialized machinery and is slower going than in the open, meaning more hours worked per the same distance above. In addition, more area has to be maintained owing to that portion of the structure above the road bed.

In the final analysis, I'd say it's a coin toss, but if there is an edge, I would say the tunnels are more costly to maintain.

Answer 3

Tunnel because you have to close the line off for men to work on track. You don't necessarily have to do this outdoors.

Answer 4

My god, you must ask the most boring questions on here.

You could send an all-night raver on pills to sleep.

Who cares about the cost of maintaining the underground. If you do, why not google it, I'm sure it's easy enough to find (I have no idea why you'd want to though).

Answer 5

I'm guessing tunnel