In the message de ...
Stuart" wrote :

Michael Bell wrote:
It is a fairly obvious feature of railways south of the river that
many run at roof level.
I once got into correspondence with somebody who said "It is the
long-term objective to put these routes underground".

I felt like asking "Are you on the same planet as me? The cost
would be astronomical, and for what benefit?", but I let it drop.


Well yes and no, they run at a relatively flat uniform level it's the
land around it that determines whether the line is level with roofs. SO
most railways I can think of alternate between being on embankments and
in cuttings

SNIP

Surprisingly, perhaps, railways in notoriously flat countries like the
Netherlands and northern Belgium have numerous 'roof-level' and underground
sections. In many cases these replace tracks that were previously at ground
level, so as to eliminate the nuisance of frequent level crossings. To avoid
long interruption to train services, the new tracks may have to be on a
different alignment.

An interesting example in this context is Antwerp, where the original
ground-level approach to Central station was replaced by a viaduct circa
1873 (when Central station became a terminus and its northern approach from
Antwerp Dam was diverted to run on viaduct alongside the city's eastern
wall).

Now new twin tunnels have been excavated or bored beneath the southern
approach viaduct and onwards to Antwerp Dam, in the context of the work on
the Antwerp - Amsterdam high-speed line; they will be used by all the
passenger trains that now run on the viaduct, thereby saving about 2.5 km.
For details, see my Web page at the URL:
http://home.scarlet.be/~pin02722/antwerp.htm
--
Regards,

- Alan (in Brussels)