Let me say it is a nice collection. Even I recognize some pieces. I do have the rivorossi Blue goose Sante Fe. The 4073 UP 4-6-2 is Mantua. The B&O withe the same cab number is probablt Mantua. THe wreck 4-8-0 with the same can number is Mantua. That is good news. Quality stuff. I love them I repaired one once for a friend and enjoyed it. The majority look in good condition.
Follow the Stationmaster suggestion. You could make a good paste or use tooth paste to cover it up to neutralise the acid. After that show me a picture of the bottom of the WRECK 4-8-0 since cab numbers are the same. I am worried because the frame is cast and if badly corroded it"s junk. You cannot have corrosion around the axle area .The mechanism is vulnerable here. The motor is universal. You have a few in the other engines that run.
You would be surprised about restoring shells though. DON't force any screws!!! If they break you are done. Use wd 40 if you remove the shell. More on that later.
Parts, Yarbird trains has all the stuff you need but to get WRECK up again you could buy another used one. Look at his site and find the diagram for the 4-8-0
it will have the parts listed. This is to let you know what you are getting into.
You may want to start with an easier train first. DO you own a dremel tool??
The electric motor points down at seven o clock and has a worm drive gear. It is held to the frame by only one screw. The shell has a screw up front and two back.The diagram will have it. The little steam chest and cow catcher stays attached to hold all those rods. The cab is plastic be careful not to break it.
Page 1 and 2 of the early Mikado 2-8-0 may be the best picture. One screw in the front two in the back.
Look at the Mikado 3rd, ist page. for the wreck. Let me know if you want to name it something else.
The 4-6-2 is a pacific your Light blue engine next to the wreck.
http://www.yardbirdtrains.com/YBMspecs.htm