I’ve had a few mods cause failure to load, even after disabling them.
If you’re on steam, find your train fever mods folder, (default C:\program files x86\steam\steamapps\common\train fever), and move all your mods out of there, to somewhere else for now. Then verify the game files in steam, and once done, try to start a modless game. If it works, put the mods back. If you have loads, activate them in batches and try starting a new game. It’s slow, but it’ll narrow down a broken mod.
Worked for me anyway.