With firmer ground the pedrails came off the guns and their teams of eight and ten horses were reduced to six. It also became possible to use wheeled vehicles, and in January the War Office agreed to the infantry divisions being re-equipped with wheeled transport trains. These were to replace camel transport, on the condition that drivers would be found locally, as no transfers from other campaigns were possible. Although camel trains remained important throughout the war, together with pack mules and donkeys, where roads were bad and in hilly trackless terrain, where the horse-drawn and mule-drawn wagons, motor lorries and tractors could not go, they began to be replaced. General service and limber wagons drawn by horses or mules were grouped in supply columns, with the transport wagons of the regiments, the machine–gun squadrons, and the field ambulances, to travel on easier but less direct routes. However, all these animals required vast quantities of food and water, which greatly increased pressure on the lines of communication. During the advance across the Sinai, although it was established that horses did better with two drinks a day instead of three, the volume remained the same.