At the posted co-ordinates you can see the platform of the Carrog platform for the Llangollen to Carrog railway. To answer these questions you do not need to go onto the platform. Please take care of any geokids or geohounds whilst collecting the information.
The cache can be found at N58.ABC W003 19.DEF
A = Number of windows on the end panel of the signal box + 2
B = (Number of black rungs on the signal closest to the bridge / 2)-1
C = Number of lamp posts on the platforms - 3
D = Number of ground signals
E = Number of chimney stacks + 5
F = Number of letters in the sign attached to the end of the main station building
You do not need to go onto the platform or onto the line at any point for this cache. Please take care walking along the road from the bridge to the final location.
Oh, and one final thing, you might need your wellies!
Placed with the kind permission of the land owner.