It's been a while since I've played, so I could be wrong, but I think it starts to go wrong around turn 34. Jools train ends in a 7, wilsoni in a 6.

Turn 35, Jools plays a double 6 on wilsoni's train, causing a graphic overlap with his own train. Then on wilson's turn 35, they draw and play a 6-7 which I believe they should only have been able to play on the double 6 as Jools' train was not marked, but it is placed as though it has been played on Jools' train and shows it as now ending in a 6. Jools' next play is on turn 38 when they play a 5-6 on wilsoni's train which appears to update correctly although the graphics are still a mess. Sassy_Angel then somehow manages to play a 3-5 with the 3 adjoining the 5 on wilson's train, but updating Jools' train ending to a 5. wilsoni is then able to play a 5-8 on to their own train but I think at this point it should be ending in a 3 and therefore unplayable with that tile.