Both OO and HO models from Europe and North America run on standard HO/OO track that is 16.5 mm between the rails. The scale of British OO gauge rolling stock, accessories and scenic items is 1/76, or 4mm to 1 foot. 1/72 scale (often used for aircraft and military models) is fairly close. HO is 1/87 so smaller on like for like items. Sectional track is supplied in fixed units with moulded sleeper base and joiners pre-installed, simply clip together to create a layout.Hornby and Peco Setrack have common geometries and are interchangeable. Peco is of excellent quality and made in the UK with better availability.Peco Streamline is supplied in yard lengths of flexible track and larger radius points that enables more realistic curves and individual layouts.