In the Inner Space world, local engineers have decided to go for a monorail design on their railway systems, due partly to the fact this system could be built cheaper and faster than a conventional one as well as have tighter corners and steeper gradients.The single rail has a section reminiscent of our world railway tracks (if oversize), but with the bottom flanges angled rather than parallel to the ground and supported on concrete blocks.The rail vehicles rest on flanged rollers set on top of the track, while the driving wheels are canted by 30 degrees from the vertical and operate on the lower flanges of the rail. For especially steep areas, the inner part of the flanges can be provided with racks which corespond to cogs or pinions built into the running wheels of the locomotive, providing extra grip, much like our world's rack-and-pinion railways.The locomotive is oil-fired and has two articulated trucks of six wheels each, with two triple expansion engines in between, similar to what's known in our world as a, but with a symmetrical layout.The boiler is a water-tube rather than a fire-tube design, so the outer casing doesn't need to withstand too much pressure, which also gives it it's particular triangular cross section.It's based on the naval Thornycroft boiler , but with the heat passing down the middle space from the firebox at the back towards the smoke box, like they would in a normal locomotive boiler.In our world there were a few attempts to use water-tube boilers in locomotives, such as the Brotan and the hebut the idea never quite caught on, becausedespite the fact the water tube boiler offers more surface area and is able to use higher pressures from the get go as well as make more efficient usage of heat, the water tubes are a nightmare to clean, have a tendency to leak due to vibration and the steam obtained is very wet.In the Inner Space world, however, all technological progress is tightly controlled by the, and they were the ones which decided, quite early on, that the water tube offered the best advantages and should be regarded as "the" path to be followed. (Of course, what that means is that you can always try to make a fire-tube boiler, and if it works well it might even be approved for production, but you simply won't get many customers for it, because not a lot of people are willing to go against established Church doctrine on technological matters...)Because of that, a lot more effort was put into making the design work than was in our world, which is why, by this time, we can be sure that the Inner Space water tube is a mature technology with most of it's bugs ironed out, in a way the water tube boiler of our world never was.The tender is designed to be streamlined but with a short wheelbase, so it can negotiate the rather tight corners of the rail line. Because of it's diminutive size, the amount of water and fuel it can carry are pretty limited, which restricts the usage of this type of tender to lines in highly populated areas of the Empire, where the tenders can be refilled.A longer, articulated design is also available for trains which operate in the remote reaches of the Black Frontier (literally "Northern Frontier" - the Inner Space people have their compass split into six quadrants, each corresponding to a colour -forforforforforfor).The carriage is an open design capable of seating 64 passengers in seats facing each other with tables in between and with a central gangway. It has six access doors, three a side, and contains two small bathrooms situated at the end of the carriage closest to the locomotive.It is based upon the real world British Railways Standard Steam Stock (Mk1) Second Class Open (So) Railway Carriage