Fluid wagon

Fluid wagon is a rail vehicle used to transport fluids by train over long distances. It must be loaded and unloaded by pumps placed at a train station; the wagon does not accept fluids from belts, inserters, or player inventory and cannot be filled or emptied directly without pump infrastructure. Fluid wagons are intended for bulk fluid transport where pipelines are impractical or too slow for long runs.

Loading and unloading speed depends on the number and quality of pumps attached to the wagon. Up to three pumps can be used per wagon; adding pumps reduces transfer time, and higher-quality pumps pump faster. Example full-transfer times (rounded up) for increasing numbers of pumps show this effect: with a low-quality pump set the times are approximately 42 s (1 pump), 29 s (2 pumps), and 14 s (3 pumps); with higher-quality pumps the times improve down to about 17 s, 9 s, and 6 s for 1, 2, and 3 pumps respectively. Pump quality and the number of pumps both affect how fast a wagon can be filled or emptied.

Pumps used to load/unload fluid wagons must be set up at a train stop. The train must be aligned to the rail grid so the wagon is perfectly orthogonal to allow the pumps to reach its fluid connection points. Using a train stop as a schedule destination and arriving with a fueled locomotive ensures accurate alignment. The rails under the fluid wagon must be straight rails rather than curved rails; pumps will not function if the wagon sits on curved rails or is misaligned.

Fluid wagons interact with the game’s fluid mechanics: they behave as containers that hold a single fluid type at a time and connect to pump outputs like other storage entities. Fluids moved into or out of the wagon are treated like fluid in pipes and tanks, subject to the same flow rules and pump behavior; machines and pumps can alter flow and pressure in connected networks. For long-distance transport, rail-based fluid wagons complement pipelines and barrels: pipelines are preferred for short local runs, barrels for specific handling, and rail for long distances.

• Use a dedicated pump array at the station and plan to place up to three pumps per wagon for fastest throughput.
• Ensure the train stops so wagons sit on straight rails and are perfectly aligned; use a train stop as the schedule destination and arrive under power.
• Remember pumps block backflow and can create overpressure in connected pipe networks; integrate station piping and storage tanks to stabilize supply and demand.
• Choose pump quality and count according to desired fill/unload time and throughput requirements.