I believe you will find that violates copyright law.

Some cars are paint schemes not in the regular line. I think the 2 bays are the same however. I have not had any problems with them rolling. The detail in general is better than Bachmann. Much of the Bachmann tooling is 20 years old or so.

 Better to ask on the Atlas DCC forum. Many Atlas locos have a jumper plug that must be moved to change between DC and DCC.

The purpose of soldering is to keep the curve smooth at the joint. Otherwise it is very easy to end up with a kink which will cause problems

Why not go right to Bowser. That way if you need parts or have a problem, you already have a connection. They are very helpful!

This is easy. Go back and cut out the lights you installed. If the short goes away, you did something wrong. If these have a circuit board, you are hooked to the wrong place.

Gees guys relax. MAP is legal; in the US. All it means is you can't ADVERTISE at a price below what the  company specifies. You can sell it for whatever you want. If you are st all awake, you will see ads saying "call for price" " too low to print here" and all sorts of like.  Many large companies have such a policy.

I am not at all confidant your answers are correct. First, covered hoppers have been built since the 30's. First ones were converted open hoppers. It would be impossible to get sand out of an open gon/hopper outside of shoveling if it got wet. Now some railroads did this to get sand for the dryer that fed the sanding tower. Sand in bags would be for special purposes because of the expense of bagging and handling.

The markings are reweigh date - some major work was done on the car. HAG is Hagerstown Maryland shops of the WM and the date.

Years ago there were battery powered trains from Hong Kong that were all plastic but between N and HO. The track was about HO size but the cars were smaller. I doubt there is any value except to some toy collector buyting stuff from that era.I do not know if they were ever imported by Bachmann, but it is possible since Kader (Bachmann parent company) was from Hong Kong.

Don't do it. It sags, is messy, does not hold nails, if you try to glue to it the paper comes off and is the noisiest stuff I ever had on a layout.

The Spectrum cars are based on the PRR P70 which according to the PRR T&HS are 74' long.

I sense you are a teacher since you seem to be concerned with sccools. First, they intentionally do not have schools near RR tracks because of safety issues.
Modern schools and colleges and hospitals are very large -a waste of space on a layout where space is a premium and have no relationship to railroads.
There are many churches made by European manufacturers - check the Walthers catalog.
The reason there are not contemporary stores and fast food places is purely a licensing issue due to the liability.

Well, see , you have a problem. The cars are lighted for 12v DC. DCC uses higher voltage which tends to burn up car lights. In fact Kato specifies their HO car cannot be used DCC without modifications. Walthers cars also have some problems.
First you will have to check each car to see if the lights still work and test each for shorts. If they don't test good you will have to open them up and look for burned wires, melted plastic etc. You could disconnect the wiring on a bad car so you can run it without lights.