It's not connected to consist, or route, but to activity. Same consit on same route in explore mode, and the resume works. There is no any diesel locomotive in that activity.
This is about that problem:
Warning: System.NullReferenceException: Object reference not set to an instance of an object.
   at ORTS.ControllerFactory.Restore(IController controller, BinaryReader inf) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\RollingStock\SubSystems\Controllers\ControllerFactory.cs:line 47
   at ORTS.MSTSDieselLocomotive.Restore(BinaryReader inf) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\RollingStock\MSTSDieselLocomotive.cs:line 228
   at ORTS.Train.RestoreCars(Simulator simulator, BinaryReader inf) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Physics\Train.cs:line 776
   at ORTS.Train..ctor(Simulator simulator, BinaryReader inf) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Physics\Train.cs:line 501
   at ORTS.Simulator.RestoreTrains(BinaryReader inf) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Simulator\Simulator.cs:line 925
   at ORTS.Simulator.Restore(BinaryReader inf, Single initialTileX, Single initialTileZ) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Simulator\Simulator.cs:line 331
   at ORTS.Processes.GameStateRunActivity.Resume(UserSettings settings, String[] args) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 389
   at ORTS.Processes.GameStateRunActivity.<>c__DisplayClass8.<Load>b__3() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 155
   at ORTS.Processes.GameStateRunActivity.Load() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 190
   at ORTS.Processes.LoaderProcess.Load() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 122
   at ORTS.Processes.LoaderProcess.DoLoad() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 103
   at ORTS.Processes.LoaderProcess.LoaderThread() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 74
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()


Error: ORTS.Processes.IncompatibleSaveException: Exception of type 'ORTS.Processes.IncompatibleSaveException' was thrown.
   at ORTS.Processes.GameStateRunActivity.Resume(UserSettings settings, String[] args) in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 410
   at ORTS.Processes.GameStateRunActivity.<>c__DisplayClass8.<Load>b__3() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 154
   at ORTS.Processes.GameStateRunActivity.Load() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\GameStateRunActivity.cs:line 190
   at ORTS.Processes.LoaderProcess.Load() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 122
   at ORTS.Processes.LoaderProcess.DoLoad() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 103
   at ORTS.Processes.LoaderProcess.LoaderThread() in c:\Users\James\Documents\Coding\Jenkins\jobs\Open Rails\workspace\Source\RunActivity\Processes\LoaderProcess.cs:line 74
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()