Lots of fiddly details are still being added to the KMX tamper.
The latest challenge has been to replicate the 4 pipes / cables which run from inside the engine compartment to the 'clock' side of the up (Blaenau) end bogie.
Yet again I must confess my ignorance of the workings of this machine - I do not know if they are electrical cables or pneumatic pipes, although I suspect the latter.
I've been thinking for a while now about the best way to tackle these and decided to use some ordinary single strand wire, the sort you wire layouts up with.
Plan A had been to attempt to connect these to the bogie as per the prototype. The difficulty is that the bogie still needs to swing and so the wires would need to be very flexible.
What I decided to do was to pull the wire out and use just the plastic sheath. Small pieces of wire were inserted back into each end and glued to anchor them in place on the bogie and in the slot in the engine compartment where they disappear.
But in a trial fitting with only one sheath in place I could feel a lot of resistance when I tried to swing the bogie - with all four connected the bogie would be almost locked solid.
The compromise I've ended up with is to fix the cables / pipes in a little block on the frame in line with the connection points on the bodies.
These blocks aren't prototypical either but on balance I think the cables are too much of a feature of this end of the tamper not to have something there to represent them.