I've no objection to rolling roads, and I do use one myself, but I do like to give locos a good running in on track as well. A few years ago, I made up a circle of P4 sectional track, using identical curved lengths of flexitrack (SMP, in this case), with the curve held in place by some copper clad sleepers soldered in place. Fishplates were also soldered on, and the result is a 7' 6" diameter circle of track, that can be dismantled into 16 seperate curved sections for storage.

It takes a while to set up, and currently needs to be on the floor. This in turn needs old magazines (Radio Times is quite good) to be laid down and taped to the carpet, to reduce the chances of hairs and other undesirable detritus getting into the loco mechanisms. Due to gradual 'creep' as the locos run round the circuit, the track is also taped to the magazine sheets.

Here is 1650 having it's first serious running in session, at the time of writing it is probably about half way through today's session, with 3 and a half hours of running under it's belt so far (this includes changing direction and the loco being turned round).

This process does seem to help smooth out minor imperfections in the running of a loco 'just out of works', although it won't normally get rid of major problems affecting smooth running, for which the loco will need to go back to the work bench.

Due to the time and inconvenience of setting this circuit up, I'm now planning to get an 8' diameter hollow circle of plywood cut out by a friend who has the right gear in his workshop to do this. I will probably cut the circle into four segments for storage, and glue the track to it, effecting board joints by use of stout hinges that have had their central pivots removed.