One of the tests involved running a train up the steepest section, with increasing numbers of coaches, with and without a pilot. Without a pilot, the best it could do was 4 before it started losing traction on the rails.With a pilot, they managed 8, still with some slipping from Tangmere. I stopped at 8, when smoke started coming out of the pilot engine! (...and it wasn't the paintshop smoke seen in the pictures below.)
|34067 "Tangmere" piloted by 2P 40579 (still in LMS livery) on a heavy cross-country train.|
|40579 and 34067 approach the viaduct, working hard up the gradient. |
The troublesome increase in gradient can be seen between the green and red/cream coaches.
|4F 44417 on the viaduct with an anachronistic ballast train.|
|View from a 00 microlight above the viaduct, looking along the trackbed towards the site of the tunnel mouth.|
What am I going to do about it? For now, I'll leave the track in place but won't extend it to double track. This will allow trains to be run and the weather-resistance of the track to be tested. Any new track further down-hill will have the trackbed raised so that eventually the existing track can be replaced with a maximum gradient of 1 in 50, as originally intended. The viaduct and the stretch up to the tunnel do not exceed 1 in 50.