In The Tunnel is a wonderful collection of photographs of old railway tunnels from Flickr user Phill.D.
Canal lovers will enjoy most the Standedge Tunnel set he's just uploaded. They include a diagrammatic map of the four tunnels through Standedge Hill, an aerial view, and a walkthrough of most of the unique points of the old rail tunnel used by BW vans when they accompany boats through the tunnel.
It shows the adits (cross-tunnels) that link with the canal tunnel and the only other tunnel still being used for trains - the 1894 double-tracked tunnel. He also includes a photo and atmospheric description of a train actually going past.
But beyond the photos Phill's also included a lot of text, with long and useful captions for each photo. For example, he says about the photo above:
This is one of the larger interconnecting passages between the tunnels. At this point it's best not to think you're 640 feet below ground here!
This side passage leads between the two disused tunnels. I was amazed to find the canal tunnel was directly under these heavy planks. You could see right into the canal tunnel by peering through the arch. It was too low down to get a good shot sadly.
[See also: The official Standedge Tunnel website]
[Photo above used under his CC licence - thanks, Phill!]

Thanks, Phill! I'd be interested to know more about your trip. Why did you go in, was it legit, was it part of a group, etc etc.
Posted by: Andrew Denny | Thursday, 16 July 2009 at 09:18 PM
Ha ha.
I've just found out you've blogged me.
Great words and write up from you there!
Glad you liked the tunnel trip :-)
Cheers.
phill.d
Posted by: phill.d | Thursday, 16 July 2009 at 06:19 PM
If not more so! I love these kind of investigations, thanks for pointing it out Andrew.
Posted by: Martin Ward | Thursday, 09 July 2009 at 08:46 AM
Absolutely fascinating!
Posted by: Captain Ahab | Wednesday, 08 July 2009 at 11:21 PM