road testing

[casey]

Hi,
Having recently replaced the plastice drive gear on my Spectrum 2-6-0 I thought that this last weekend I would take advantage of the good weather ( here in southern UK) and run it and the 4-4-0, A great time was had and this also highlighted another fault, namely the pony truck on the 4-4-0.
I pride myself on the fact that on open days we don't get derailments due to poor track as I find it tiresome and the extra effort in track laying is always worth it.
However the 4-4-0 always seems to find the tiniest flaw and pop off the pony truck.
Last night I turned the loco upside down and tried to figure out the problem, as after watching it going along I felt that if the truck was lower It might help, anyway I ended up removing the plate which holds the spigot for the pony truck and added 3 2BA washers (originally I was going to lengthen the screw which holds the truck but did not have the same size thread) anyway I tested this tonight and can report that this simple fix had a 100% improvement.
Now this is my question and please don't take offence as this is an attempt to try add some constructive criticism.
Before these loco's are put into production what kind of road testing is done? it is evident from the experience I have gained that some of these faults are so elementary that they should have been picked up VERY early on.
I don't know if it is practicle but is it not possible to send out a couple of pre production loco's to be tested on various model garden railroads and get the feedback, I realise that this could add a further 6-8 months to the project but there would not be the constant niggles , complaints and returns that occur as these obvious faults would in general be found.
This is something that won't be found on a rolling road testbed or an indoor track.
This is not a pop at Bachmann, all the other manufacturers tend to suffer the same (though I can't comment on Accucraft as I don't have a loco of theirs) Bachmann are certainly market leaders in general quality but it is a shame to have "the ship spoiled for a ha'peth of tar"
Regards Casey.