The trains will be run on the principle of the multiple unit. That is, each will be made up of seven coaches--three long motor-cars and four trail-cars--with a motor-man’s cab at each end, and one in the centre. These eight-wheeled coaches will be rectangular at the sides--not sloping like those of the Waterloo Tube Company--and very roomy, 52 feet long and about 8 feet 2 inches wide inside, and about 8 feet 7 inches from the floor to the middle of the roof. [Illustration: FIG. 10. A NEW METROPOLITAN DISTRICT RAILWAY CAR _By permission of the_ _Underground Electric Railways Co. of London, Ltd._] The arrangement of the seats will be somewhat different from that of the Tube. There will, of course, be corridor cars, which will be entered from the platforms, through telescopic doors; there will be also sliding doors. The gain in leg-space will be great, the centre gangway giving a clear 4 feet, and there will be fewer cross seats. Each train will hold about 338 passengers; the ventilation of the cars will be perfect; and the height sufficient for a giant. As the District tunnels are 25 feet in diameter, and 15 feet 9 inches from the rail level to the crown of the arch, there will be about 2 feet of head-room, about 2 feet 6 inches between each train, and the same between the trains and the sides of the tunnels. Compare this with the present Inner Circle trains that carry about three hundred passengers, with gangways that, even in the first-class compartments, leave no room for incomers to avoid a leg entanglement, and whose height will hardly admit a tall man in a tall hat to stand upright. Also compare it with the dimensions of the Central’s cars, which are 39 feet long, 8 feet wide, and whose height to the middle of roof is only 7 feet 5 inches, the gangway narrow, with seats in each car for forty-eight people. The space in the cars of the City and South London, and the Waterloo and City, is still more exiguous. It is proposed to run about twice as many trains as at present, each journey to be made in about two-thirds of the time now required; that is to say, the trains that now run about ten miles an hour will, it is anticipated, work up to at least fifteen miles; the total carrying capacity being estimated at 70,000,000 per annum, increasable, if necessary, to 100,000,000. There may be an all-night service, for the convenience of people engaged at Covent Garden market, and for journalists and others whose work lies in the vicinity of Fleet Street. A somewhat novel and economical feature will be that the trains, during the stock hours of the day, can be run in short lengths, as in the City and Waterloo Railway, and, with their triple motors divided, will resemble those strange Naidæ worms of the Annelida class that possess the power of increasing by mechanical division. They will also be able to go forward and backward without reversing the motor engines.