There is off-road parking for 1 vehicle right in front of the gates.
See historical notes for 'Old Craigenhill Level Crossing - South Side. As well as the level crossing in front of you, there used to be a tramway that ran from close to GZ, parallel to the track, to the former Lime Works. See old map below.
On the railway, underneath the track shoes are placed rubber pads. These are about 200 mm square. They probably aid passenger ride, but their main function is to provide some electrical resistance between the rails and ground. The coordinates given are for one of these pads (don't worry, it's not in its original location). The cache is not behind or under the pad, so there is no point in trying to remove the pad from where it is placed (in full view and near to ground level), however, it is under 2 metres from it. I took coordinates for the container, but they came out the same as for the pad.
BYOP