The Westinghouse air-brake has a retarding force of three miles a second. It would therefore arrest a train travelling at 110 miles per hour in 37 seconds, or 995 yards. Mr. Behr proposes to reinforce the Westinghouse with an electric brake, composed of magnets 18 inches long, exerting on the guide rails by means of current generated by the reversed motors an attractive force of 200 lbs. per square inch. One great advantage of this brake is that its efficiency is greatest when the speed of the train is highest and when it is most needed. The united brakes are expected to stop the car in half the distance of the Westinghouse alone; but they would not both be applied except in emergencies. Under ordinary conditions the slowing of a car would take place only at the termini, where the line ascends gradients into the stations. There would, however, be small chance of collisions, the railway being securely fenced off throughout its entire length, and free from level crossings, drawbridges and points. Furthermore, each train would be its own signalman. Suppose the total 34-1/2 miles divided into “block” lengths of 7 miles. On leaving a terminus the train sets a danger signal behind it; at 7 miles it sets another, and at 14 miles releases the first signal. So that the driver of a car would have at least 7 miles to slow down in after seeing the signals against him. In case of fog he would consult a miniature signal in his cabin working electrically in unison with the large semaphores. The Manchester-Liverpool rail will be reserved for express traffic only. Mr. Behr does not believe in mixing speeds, and considers it one of the advantages of his system that slow cars and waggons of the ordinary two-rail type cannot be run on the monorail; because if they could managers might be tempted to place them there. A train will consist of a single vehicle for forty, fifty, or seventy passengers, as the occasion requires. It is calculated that an average of twelve passengers at one penny per mile would pay all the expenses of running a car. Mr. Behr maintains that monorails can be constructed far more cheaply than the two-rail, because they permit sharper curves, and thereby save a lot of cutting and embankment; and also because the monorail itself, when trestles and rail are specially strengthened, can serve as its own bridge across roads, valleys and rivers. Though the single-rail has come to the front of late, it must not be supposed that the two-rail track is for ever doomed to moderate speeds only. German engineers have built an electric two-rail military line between Berlin and Zossen, seventeen miles long, over which cars have been run at a hundred miles an hour. The line has very gradual curves, and in this respect is inferior to the more sinuous monorail. Its chief virtue is the method of applying motive power--a method common to both systems.