So much explanation is necessary to give some account of the alternating current railways on the Continent and thence of the single-phase system on the London, Brighton and South Coast Railway. The Morecambe and Heysham section of the Midland Railway is also equipped on the single-phase system. Most of the earliest electric railways on the Continent derived their power from waterfalls and had to transmit it for a considerable distance. Three-phase current at high pressure being adopted for this purpose, the Continental engineers set to work to find some means of utilising the high-pressure three-phase current directly. They did this by carrying the three wires on poles alongside the railway track, and using three 'bow' collectors (in place of trolley wheels) to convey the current to transformers on the motor cars or locomotives. In these transformers the current was brought down to working pressure and then led to motors designed for three-phase current. An immense amount of technical ingenuity was exercised in developing this system; and when the Metropolitan Railway decided to follow the District in electrifying its lines, a three-phase system was proposed. As the Metropolitan and Metropolitan District companies share the working of the Inner Circle, it was necessary that both should adopt the same system. The result was that the question between three-phase and continuous current working had to go to arbitration. After a long discussion of masses of technical evidence, Mr Lyttelton, the arbitrator, decided that the direct current system was better suited to the conditions of traffic on an underground railway in London. The wisdom of that decision will not be questioned now. Three-phase motors do not give the rapid acceleration which is so urgently required on suburban lines; there are complications in speed control; and the necessity of having three overhead conductors is also a serious drawback. For comparatively long-distance traffic with few stops, however, the three-phase system is quite suitable. That is to say, it is a possible solution of the main line problem. The great simplicity and flexibility of the power supply arrangements in the case of alternating current traction encouraged engineers to find something better adapted to ordinary railway conditions than the three-phase motor. Their problem was to find an arrangement which required one overhead conductor instead of three, and also provided a motor with the high starting torque and easy speed control of the continuous-current motor. After much theoretical and experimental work, they found it in the single-phase system, using a motor which is similar in many respects to the continuous-current motor but capable of being operated by alternating current.