Talyllyn Adventure Route Update Patch

NOTE: This Mandatory Patch Updates the Talyllyn Adventure Route Pack to v2.5.2
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This Route Update includes all prior fixes and enhancements from multiple packs into a single consolidated patch.

This patch fixes:-
(1) The standard rolling stock (passenger & locos) to use new couplings to reflect current  TR standard couplings.

(2) Corrects coach bounding box values to improve buffer and collision parameters and improve  passenger window glass visibility.

(3) Adds new assets and functionality around the Forestry Road Crossing area with new Forestry Crossing road and rail warning lights

(4) Watering facilities at Ty Dwr and Dolgoch Station (down).

(5) Multiple minor fixes across the route.