Help with railway mileage.

[swt_passenger]

I was amused to see on the HS2 official maps (Arup) that while the route is clearly identified in metric (km, shown to .001 ie a metre), that the actual distance measure was called "Chainage"....

That's OK, there are metric surveyor's chains which are 20m long...

 

[ChrisD]

Some information here.
http://kentrail.org.uk/Cheriton.htm

Thanks Clive - seen this before and it confirms the tunnel length ("some 31.35 miles") but not the actual distance from the loading to unloading points.