With all due respect, the 15's block WAS cracked; I saw it myself. The crack was longitudnal between two or three of the cylinder holes, in the bottom "floor" or web of the block casting. The 240 had a similar crack, in the same place, except that one ran from the rear of #1 jug to the front of #6 jug.
15's engine had been rebuilt by M&E with a load of very nice new parts, shortly before it went to VRR. It had terrible wheels (thin tread and flanges) in roller bearing trucks. It also had been rebuilt by M&E with26 brake and an EMD roller switch throttle. Was built in 1944 as US Navy #6 for Dahlgren Proving Ground, complete with steam generator (later removed).
VRR owed AJB some bucks for a track job, and #15 was part of the settlement.
There was legal action (or the threat thereof) between 240's private owner and the VRR, which was settled in some way; the replacement 539 block referred to above went with that settlement. 240's owner sold the unit to Hockaday, along with the block.
There was no legal action re: the 15.