I am not a member of ORTS but I can say that each new X release does contain all fixes to that date, which is what should have been stated. Therefore...
The error is telling you that the activity needs sd402.eng to be in Trains\trainset\sd402. Deleting anything will not make the error go away. You get...
The more normal way would be to lay the track across the gap, then add the bridge under the track. To do what you want, maybe the Object box can help...
Changing UAC to quiet mode does lower the overall security of your computer because it will not alert you to anything unauthorised. However, if this...