from reading through all this, my guess is the poster has a lot of train set quality cars which are notorious for having trucks too tightly mounted to allow any flexibility. This explains both the derailing and lack of rerailing. The trucks have to have some movement in all 3 dimensions in order for the wheels to be  redirected. If the trucks only swivel and do not have some slight tilt from side to side they are too tight. This can be difficult to correct in train set cars which are often pinned to the floor instead of screw mounted

The ones I am familiar with marked where a power line or signal wires passed under the roadbed so maintenance crews don't tear up the cable

I ran a molding operation for a model RR company for years. Generally the warped trucks are from sticking in the mold and twisting when ejected. The twist is molded into the memory of the plastic and will return to the twist regardless of heat or pressure. Just throw them away and replace.

508 Kadees replace the long x2f with a plastic bar  with the Kadee out at the end so they are still truck mounted (required for typical curves). Body mounting requires curves in the 25-30 inch range. The 508 are screwed to the IHC frames after some changes by cutting away a small amount. Kadee will probably send you a copy of the instructions, or just buy a set to see them.

Actually to find the value you need to get away from these train guys. There are people who collect by brand name(not the railroad maker) who pay good money for this type of set. Some of the Athearn ones have gone for around $400.  What you need to find is someone who collects Zenith materials.

Everyone assumes Hornby has all the Rivarossi tooling. Maybe, maybe not. It may not be in shape to run even if they do have it. Also it looks like the prices are quite high.  I think you will see a slowing of product from Lifelike as the market and Walthers can only handle so much. It looks like the Bachmann Berk will be a good unit at a popular price point. I think it a good move by Bachmann. PM 1225 and Polar Express made a huge impression on the general public .A lot of people whose kids saw the movie will likely be  a sale. Licensing will prevent Bachmann from marketing it as "Polar Express" (even the 1225 can't use that marketing any more).

Gene I was thinking about this last night. I think the perceived difference is mostly fantasy. First, the same item is rarely made in both lines.  I believe thew difference is the price point Bachmann intends to sell the item at. It's like the difference between a Chevy and Cadillac. You think you are getting more, but both will get  you to work on time.  Is the Cadillac better? Maybe. It may look better, will cost you more, and makes you feel better.  Bachmann QC even on Spectrum has always been suspect.  I now think Bachmann takes an elitist attitude with the Spectrum line - you will feel better about spending more money for the more expensive item. On the other hand, with the new Berks, Bachmann is appealing to the masses - everybody can afford one!

Probably just needs a resset. Do you know how to do this?

Many "oils" are not plastic compatible.  Jim, you should define what you are using. Wahl clipper oil has been used. A better solution is a product called Rail-zip.

Don't really want to get involved, but the reason HO is no good outside is the track is not UV stabilized and deterioates very rapidly in the sun. The large scale stuff is all UV stabilized.

Get an NMRA guage and check the wheel spacing. You have a wheel out of guage.

Please post FACTS. Bevbel is not out of business, though they don't have a large line because most of the cars are now Athearn RTR.
Robins Rails had some of their own cars and did paint jobs on Concor. They have been out of business since the 1980s. CM shops is out of business for several years now.
Horizon did not kill the market for anything. The fact is they have the capacity to use all their production in house and do so. Much of the Bevbel and CM lines would be redundant since  the same cars are better done in the RTR line.

As Nigel points out, you need to learn how to search for what you want. Start with the model - "Bachmann Shay". If you don't get what you need, try "Bachmann Shay decoder". Every decoder company has their own site. Many have complete instructions. There are also independant places like Tonys Train Exchange. You will fimd more material than you could ever read.

Crown was the old Varney tooling moved to Hong Kong. They only lasted a year or two. The cars  were sold on blister cards for less than a buck. They were not very good and quickly went out of business. The tooling eventually ended up as Lifelikes train set (poor) quality stuff.

Changing couplers is one of the first things you need to learn. Since Kadees cost more than the cheap plastic ones, Bachmann and others don't use them. You have to pony up the money yourself.