TS12 Corrupted session file?

I have created a route which now has three AI sessions attached. The latest one has nine consists with fairly lengthy schedules.

I edited the route (added a bridge across a stream) and saved it. From the main menu I selected the session and "Edit Session". The map showed in one part of the layout a spiders' web of tracks. It was far too messy to edit so I exited Surveyor and went back to Edit Route. Here the track was fine, including my added bridge. I loaded an older session, which was OK. I can't imagine what caused the problem apart from a file somewhere suddenly corrupting.

Ideally I need to be able to print the list of drivers' schedules so that I can enter them in a fresh session, i.e. without having laboriously to write all the waypoints and details of trains from the screen first. I can't see that the schedules are filed in a legible form anywhere, but one of you might know a secret.
Hi Orpheus - If you are using TS12 HF4 (or maybe as low as HF1) you can copy all the rules to another session of the same build.

As a precaution, first save the routes to cdp files in case something goes wrong.

Open your defective route, Edit the session. Select as many of the rules as you want to by holding down Shift or Control keys and clicking on the rules. They will turn an orangy yellow colour. Then Right-click the selected items and select Copy.

Now close that route and open your good route, Edit the session. Right click in the window and select Paste. Delete any original commands that are duplicated. Practice on a test route first.

You can also copy the rules and paste them into a text document to capture the text. A table of kuid numbers would be needed to identify which rules they are. Unfortunately, copying from a text file will not result in the rules appearing in a session.

This was working in earlier versions of TANE but was broken in HF2 and the text facility has not been fixed in HF4, although you can now copy and paste rules in TANE HF4. It doesn't work between TS12 and TANE.
That sounds good, Trev. I'll try that as soon as I get time. In future I'll discipline myself to document details as I go.