Fluid wagon

A fluid wagon is a rail vehicle used to transport fluids by train. Unlike ordinary cargo wagons, it can only be filled and emptied with pumps, so it is part of the game’s dedicated rail logistics for liquids rather than item transport. It is most useful when a base needs to move large volumes of oil products, water, or other fluids between distant outposts and production centers.

To transfer fluids into or out of a fluid wagon, a train station with pumps is required. The wagon must be aligned to the rail grid: the pumps only work when the wagon is perfectly orthogonal to the grid, with the rails under it being straight rails rather than curved rails. In practice, this is done by making a train stop a schedule destination and using a fueled locomotive so the train can position itself correctly at the station.

Loading and unloading speed depends on how many pumps are connected to each wagon. A maximum of 3 pumps can be used per wagon, and adding more pumps reduces transfer time significantly. Pump quality also affects pumping speed, so higher-quality pumps transfer a full wagon faster. The full-transfer times below are rounded up:

• 1 pump: 42, 33, 27, 22, or 17 seconds, depending on pump quality
• 2 pumps: 29, 17, 14, 11, or 9 seconds
• 3 pumps: 14, 11, 9, 8, or 6 seconds

Because fluid wagons are limited by pump throughput, station layout matters. A well-designed loading or unloading station should keep the wagon straight, leave enough room for pump placement, and use multiple pumps per wagon when faster transfer is needed. When a station is not aligned correctly, the pumps will not connect, even if the train is stopped at the right place.