Well that also opens the Service Editor. Every time the Service Editor is opened the AE reads the Trainset database and reports errors. Sounds like you have errors, such as typographical errors, in the ENG, WAG and/or CON files. By typographical errors I mean KN written for MaxPower. KN = Force not Power. Should be KW not KN. Or the Activity is calling for rolling stock that you do not have. There could be so many errors that the buffer space set aside too store the errors is overloaded.
So back to my unanswered question.
Have you tested all the ENGs, WAGs and consists in your Trainset with programs like ConBuilder and Convoi? And if so have you corrected all known errors? Critical errors in ENGs and WAGs will cause this sort of crash with no error message.