Water Capacity
Water capacity indicates how strong the wagon or engine can withstand heat before it starts burning. The game uses seconds(s) to indicate water capacity where value indicates the number of seconds it will take for the wagon/engine to burn under a single heat source.
Heat Sources
There are multiple heat sources in the game. The rate of which they consume water capacity is identical (1s of heat capacity per second).
Engine
All engines generate heat while it's moving after the countdown is over.
Fire
Fire can heat up nearby wagons.
Engine is not affected by fire.
If there is fire on both sides of the wagon, the wagon do not heat twice as fast.
Hydro extension
Hydrocharge extension causes the wagon to heat up whenever it is active. If multiple Hydrocharge extension are added, water consumption rate is multiplied.
Turret
Turret wagon heats up itself whenever it is shooting, as if it already contains a hydrocharge extension.
Water Capacity
Engines have different water capacities. See Engines for details.
Most wagons except for Turret Wagon have an initial water capacity of 30.0s.
Hydrocharge can increase the water capacity of a wagon by 20.0s each.
Water capacity of the wagons are separated, except for Tank Wagon. See Tank Wagon for details.
Example
If the first wagon has 3 hydrocharges, the wagon has 30.0s + 20.0s * 3 = 90.0s of water capacity.
When the wagon is active, it would take 90.0s / 3 = 30.0s for it to start burning.
If the engine is on fire and the wagon is not active, it would take 90.0s for it to start burning.
If the engine is on fire and the wagon is active, it would take 90.0s/ 4 = 22.5s for it to start burning.