Demo trains not recognized at Museum

[nxfs11]

I found the DE2 and DH4 and got them restored at the museum just fine. But I also have the DE6 and DM3 and neither are recognized by the museum, so I can't buy parts or repair them. And the service station says no vehicle.

Is there something I can do to get the museum to find them so I can pay for the restoration to start at the office?