"Tom Anderson" wrote in message
rth.li...
On Fri, 5 Jun 2009, Tom Anderson wrote:

On Thu, 4 Jun 2009, John Rowland wrote:

Tom Anderson wrote:

Or, of course, you could dive, and build some platforms in tunnel.

And sever the Regents Canal?

Underground locks.

I had a bit of a look to see if there was such a thing as an underground
lock, and i couldn't quite find any, although i did find an underground
inclined plane:

http://www.d.lane.btinternet.co.uk/canal2.htm

Does anyone know of an actual underground lock?


No, but this might help. Depending on the required gradient on the tracks,
you could conceivably cross the canal on the near level, traditionally this
would have involved a swing bridge. However a 'drop lock' (or sump lock) has
been provided for the Forth and Clyde restoration to allow the canal to
effectively burrow under a road, the same could be done under a railway:

http://www.gentles.info/link/Drop_Lock/Drop_Lock.htm

Paul S