EMD 645 Now 'Difficult to Find Parts'?

This isn't about EMD locomotives exactly but the EMD 645 engine. I read this proposal to re-power one of Virginia Dept of Transportation's ferries, The Pocahontas. Here's a quote from the proposal:

"The Pocahontas was placed in service in 1995 and was outfitted with 2 EMD 645, Series 1 engines. These engines 
were rebuilt used engines and were originally manufactured in 1974 & 1976. Presently these motors are not 
supported by the manufacturer and are becoming increasingly difficult to find parts for when needed. On occasion 
a nationwide search for parts will prove to be unsuccessful and then the part will have to be manufactured. At 
times this can produce a lead time of 120 days. Some parts are no longer manufactured at all."

Does that sound right? AFAIK even in the not too distant past, EMD 645 parts were maybe the most available of just about any diesel of comparable size, manufactured by all kinds of people besides EMD itself. Has this really changed, or is it a matter of a purchaser like a state agency demanding only new parts produced by the original manufacturer, or what? Is there any similar case in the railroad world?

Joe

I (think) I sent you a private message about this matter. Since then I thought that that based on the build date you'll have to rebuild them with the correct parts to meet at least tier 0 emission standards. The problem is that you as an independent contractor that doesn't own the engines you won't be able to buy parts at all without arraigning some deal with Virginia State Ferries and EMD.