Part of the pre-exhibition testing process has been taking a look at Merddin Emrys to see why our oldest Fairlie has been getting a bit arthritic of late.
It had to be restricted to light duties in service on Bron Hebog at Dinas because in one direction is was reduced to a crawl at full power when running with a full rake of FR stock.
The difficulty with these Backwoods Fairlies is that the motor is not accessible for servicing - it is built into the body at an early stage of construction.
Himself's greatest fear is that it should fail completely or become burnt out.
One theory he had was that during the servicing he carried out on the bogies prior to the Dinas show, he might have got the drive shafts mixed up, or somehow not located properly.
He's reported back that he's had a fiddle with it and it seems to be performing a bit better.
Let's hope so.