The boilers are inclined on the locomotives, to ensure that the boiler tubes and the firebox remain submerged when on the gradient, a standard practice on mountain railways – the locomotive always runs chimney-first up the mountain. The water gauges (gauge glasses) are mounted half at the centre on the locomotive so that the water level does not change with the gradient. One result of the boiler's angle is that the firehole door is at waist height, requiring the fireman to lift the coal some distance. The boiler is not superheated. Water is carried in tanks that run the full length of the boiler, but not all this water is for use in the boiler. The tanks are in fact divided into two sections, the smaller front section holding water that is used for cooling when the engine is running downhill. The drive to the wheels is through a series of levers that allow the pistons to have a longer stroke than the cranks. This is another common feature in mountain railways.