Talking about a fast learner here, Man you show progress, keep it up. As for the box, you could use a terrain to create a polystyrene (if that is the word???) case to fit al the parts of your model train. Its just an idea. And maybe for a next model, curved rails?

Robert van der Veeke Basugasubasubasu Basugasubakuhaku Gasubakuhakuhaku!! "Better is the enemy of good enough." Dr. Mikoyan of the Mikoyan Gurevich Design Bureau.