Complex sentence: Porthdinllaen is now owned by the National Trust, while much of the 1800 embankment was re-used by the Croesor Tramway, and is now the route of the Welsh Highland Railway, and is regularly traversed by Garratt locomotives from South Africa.
Split into simpler sentences: Porthdinllaen is now owned by the National Trust, while much of the 1800 embankment was re-used by the Croesor Tramway. It is now the route of the Welsh Highland Railway, and is regularly traversed by Garratt locomotives from South Africa.