It looks nice. Pay attention to the details included that provide some operating fun and some scenic elements.
- larger radius curves
- a passing siding
- an engine shed with a yard lead
- ability to reverse direction of train
- a lift-out bridge
- an industrial siding for buildings or operating accessories
A triangle would cut out some large radius curves.
Do you have software to play with the design?
What's the outside dimensions of the space and the point of entry?