For space I have a basement that is 24x40 ft (7.3x12.1m) (excluding stairs and walls), the grid squares represent 150mm I believe, (the metric system is uncharted territory for me) the trains, are stopping passengers and goods from the stone quarry, the signal box I neglected to add to the plan, is meant to be left of the goods shed facing the track the leads into the yard, the two goods sheds, are meant to be operated by different companies, (one for public transport (on the left), the other for private companies (on the right). The run around in the sidings are for stone trains which come in from the front then run around, the engine shed should be no more than 6 inches (152.4mm)