Hi mstsrocks,
Your username can be whatever you like.

Most of us on here like to reply with First Names it's more friendly. But thats your choice.
It is unlikely the coupling change would cause a brake problem.
However, the Orient Express Rake used is Air Braked, Clan Line is Vacuumn Braked.
How is EWS 67006 set up? I think that is Air Braked/Automatic coupling as well.
You may be able to Uncouple this consist but it will not recouple.
If you changed the Bar coupling in the Clan Line.eng file that is the one between loco and tender. To change the Engine to train Coupling do the Chain coupling on the tender *****.wag file
I guess you are using MSTSBin from your refrence to Cab Swapping. Do you realise that when you swap Cabs with MSTSBin all the controls are zeroed and have to be selected again. So the Handbrake/Loco Brake will be on.
In a case like this. It is advisable to check each item in turn to find the problem.
If you have the Clan Line Downloaded File backedup. Reinstall it over the one you have. Overwriting all files when asked.
Make a Consist of Clan LIne, light engine, and check that in Explore Mode.
Then Download a Set of Pullman coaches from UKTS
 | |  | BR Pullman Carriages Parlours Brake. [821178 bytes] - BR_Pullmans_Palours_3rd.zip File ID: 514 Date: 08 Jan 2002 - 5005 Downloads |
|
 | |  | 1st Class Pullman Parlour Cars [819532 bytes] - 1stPullParl.zip File ID: 529 Date: 30 Jan 2002 - 5477 Downloads |
|
will do.
Before installing them check the *****wag files and change the couplings if necessary.
Or if you have 'The Southern Railway' from Just Trains use the Pulmans in that
Then make a Consist with those and Clan Line.
Then check the Cl 67**** and amend to match the train.
That is enough to be going on with
Come back and let us know how you get on.
Good luck
Doug