HISTORY OP CIVIL ENGINEERING IN NEW SOUTH WALES. 619 



BLOCK SYSTEM AND BRAKES. 



The block system which ensures that no two trains shall be on 

 the same section of the line at the same time, is partially in force 

 on a considerable length of the New Soutli Wales llailways; and 

 on all single lines the staff and ticket system is strictly carried 

 out. Bet\%een Sydney and Parramatta, and at many of the im- 

 portant station-yards throughout the colony, the absolute block 

 system is in foi'ce in conjunction with the interlocking system, 

 which consists of the mutual interlocking of the levers which 

 actuate the points, signals, and gates of level crossings, and 

 collecting them altogether in a signal-box placed in a prominent 

 position. Special arrangements exist to minimise the danger of 

 facing points where they cannot be avoided altogether, as at the 

 entrances of terminal stations, so that the points cannot be moved 

 while a train is passing over them, and they are held closed, or 

 fully open, as the case may be, the operations being completed by 

 the movement of a bolt by means of a lever in the signal-box, 

 which is interlocked with those actuating the points and signals. 

 This system is so arranged that the signal for a particular train to 

 pass cannot be given until the points are moved in the proper 

 position for that train to pass in safety ; and it is further provided 

 that the consent of the signalman in both the home and distant 

 signal-boxes shall be given before the signal is given allowing the 

 train to pass into the section. The movement of the levers which 

 ensures this result locks all other levers, whether for points or 

 signals which might allow a train to pass at the same time as the 

 train in question and produce a -collision. 



Brakes : The passenger trains are all fitted with the automatic 

 continuous air-brake, the merits of which ai'e generally admitted, 

 and it is also proposed to fit up goods trains with a suitable 

 automatic continuous brake, which will ensure the stopping of 

 the train under all conditions of ordinary work and emergency, 

 as well as the complete control of its speed down the long and 

 steep inclines which have already been referred to. 



The author is indebted to Mr. John Wliitton, M. Inst. C.E., 

 Engineer-in-Chief for Railways, for complete sections of the 

 railways, and for various particulars on bridges, tunnels, 

 &c. ; and to Mr. J. Middleton, Locomotive Superintendent, 

 for the list of particulars of locomotive engines and rolling stock ; 

 Mr. W. C. Bennett, M. Inst., C.E., Commissioner and Engineer- 

 in-Chief for Roads; Colonel Wells, and Mr. J. A. McDonald, 

 M Inst. C.E. 



TRAMWAYS. 



The first public tramway established in Australia was con- 

 structed from Redfern along Pitt-street to Circular Quay, and 



