6. The levers by which points and signals are worked to be interlocked and, as a rule, brought close together, into the position most convenient for the person working them, in a signal-cabin or on a properly constructed stage. The signal-cabin to be commodious, and to be supplied with a clock, and with a separate block instrument for signalling trains on each line of rails. The point-levers and signal-levers to be so placed in the cabin that the signalman when working them shall have the best possible view of the railway, and the cabin itself to be so situated as to enable the signalman to see the arms and the lights of the signals and the working of the points. The back lights of the signal lamps to be made as small as possible, having regard to efficiency, and when the front lights are visible to the signalman in his cabin no back lights to be provided. The fixed lights in the signal-cabin to be screened off, so as not to be mistakable for the signals exhibited to control the running of trains. If, from any unavoidable cause, the arm and light of any signal cannot be seen by the signalman they must, as a rule, be repeated in the cabin. 7. The interlocking to be so arranged that the signalman shall be unable to lower a signal for the approach of a train until after he has set the points in the proper position for it to pass; that it shall not be possible for him to exhibit at the same moment any two signals that can lead to a collision between two trains; and that, after having lowered the signals to allow a train to pass, he shall not be able to move any points connected with, or leading to, the line on which the train is moving. Points also, if possible, to be so interlocked as to avoid the risk of a collision. [Illustration: Fig. 10.] Home or starting signals next in advance of trading-points when 24 lowered, to lock such points in either position, unless such locking will unduly interfere with the traffic. A distant signal must not be capable of being lowered unless the home and starting signals in advance of it have been lowered. 8. Sidings to be so arranged that shunting operations upon them shall cause the least possible obstruction to the passenger lines. Safety-points to be provided upon goods and mineral lines and sidings, at their junctions with passenger lines, with the points closed against the passenger lines and interlocked with the signals. 9. When a junction is situated near to a passenger station, the platforms to be so arranged as to prevent, as far as possible, any necessity for standing trains on the junction. 10. The junctions of all single lines to be, as a rule, formed as double-line junctions.