The use of transport and supply motors does not amount merely to the employment of a large number of these machines for miscellaneous duties, but rather corresponds to bringing into existence a new link in the chain of the main system of supply. The existence of railways behind the army is assumed. At some safe point along the railway is formed the base, and from this base stores are brought up to a point known as “railhead,” This is the point where, for the time being, military rail traffic ceases. It is evident that railhead is a variable quantity, liable to move forward or backward from day to day. The main accumulation of stores is at the base, and the stock at railhead at any moment consists only of sufficient to meet one day’s requirements. Before the introduction of motor transport, the whole of the supplies from railhead had to be taken by horsed vehicle, and subsequently distributed in the same way among the troops. Under the new method, motor lorries carry the supplies up to a place called “re-filling point,” which is a movable point situated from day to day in the most convenient position possible to arrange, with a view to the distribution of supplies by horsed vehicle to the army. In the old system, the transport vehicles worked in _echelons_. The first of these, with the baggage and supplies for a day, followed so closely behind the troops as to be able to join them every night. The next, half a day’s march behind, carried supplies sufficient to replenish the first column daily. Further back again were other _echelons_ carrying on the same scheme. This meant that the whole of the roads for enormous distances behind the forces were encumbered by transport. Between railhead and the army there were many links involving endless possibilities of confusion, and consequently shortage in supplies. Moreover, food came up to the troops very slowly from the base, and it was impossible to supply a regular stock of fresh meat and bread. The advantage of the new system is based on the speed capacity of the motor vehicle, a supplementary point being an enormous reduction in the length of a column carrying a given quantity of supplies. It is, however, the higher speed of the motor which has the greatest effect, since it enables many columns to be replaced by one. In the words of Colonel Paul: “One _echelon_ of mechanical transport can do the work of five _echelons_ of horse transport, and one column will suffice to connect the horse transport immediately behind the troops with the railway.”