Technical

I have just come back in from the garage from unsuccessfully trying to run my Silver Link & Mallard on the rolling road.

Both of them will raise steam and blow safety valves perfectly, but when put into regulator open position neither can turn their wheels, even assisted they can't do it. This is a bit soul destroying as both of their running conditions have deteriorated over the course of their last 5 steams despite my best efforts at changing seals recently to make them run better.

Silver Link ran absolutely fine at Manchester 2018 show and they ok-ish at Warley, has done a maximum of 10-15 hours running.

Mallard used to run ok years ago, then went to John Humphries at Hornby last year for some seal replacements and a check over, then ran ok only once on a rolling road before managing half a lap on the club layout at Warley. It then ran poorly on the rolling road last week before I changed the piston/gland and Reversal Unit seal cushion.

The only thing I can think of in each case is that in changing the Reversal Unit seal cushion (on both) I've not reassembled the unit correctly:

The graphite washer is ok on both (as this is what I was checking mainly), the only other thing I've done differently is using the club's recommended 2-3 drops of steam oil as opposed to the booklet's 0.5ml. It's seems like they're not sending steam down to the cylinders at all and hence why I think I've done something in the unit re-assembly.

Can anyone advise what the best thing is to do with both? Or whether they've had these issues before? I'm tempted to send them to John Humphries to see if he can find the issue, but given the Mallard has only done 4 steamings since returning from Hornby I'm a bit tentative.

Any help anyone can give is greatly appreciated!

Many thanks, Alex.