Penn Central subsidiary the Lehigh Valley RR recently sent an FA-FB-FA set of engines to the New York Central Train Layout Locomotive shop for evaluation and possible repair. The N.Y.C.T.L. Shop Foreman inspected the units and found 1 FA unit with no defects noted. 1 FA and the FB unit were found to have severe structural frame cracks and outer shell damage. These two units were immediately removed from service and brought into the shop. After several days the FA unit emerged from the shop and was put back into service. The FB unit however could not be repaired it's frame is damaged beyond repair.
So what exactly is going on? Zinc-pest or zinc-rot as it is commonly known.
This issue has been plaguing these Walthers models for years. This is the second time I have addressed the issue of expanding and cracking frames with these specific units. I contacted Walthers earlier this year to see if I could purchase new frames but was informed there were none available and none expected. I also have a couple of A.T.S.F. units that suffered from the same issues and needed to be replaced.
In 2012 I posted here about the problem with these engines;
Check the link. It has a lot of pictures of the issues that won't go away.