AUTOMATIC SPEED RECORDERS

Shannon News, 8 October 1929, Page 4

AUTOMATIC SPEED RECORDERS

NOT NOW USED ON RAILWAYS.Asked whether the Railway Department eirfployed any mechanical means by which the speed of trains could be automatically registered, a railway official said that automatic speed recorders had been employed for a while. These instruments registered the speed and kept a record of it on a tape. They were geared to the wheel in much the same way as a motor-car's speedometer, but had additional equipment ( in the form of a time clock. The relation between the speed and time was what was wanted, and this mechanism enabled the speed of the train to be read at any desired point on its journey. These, recorders proved very costly and difficult to maintain in running order under service conditions and are no longer, regularly used, but only for special tests. Apart from any automatic installation railway officials have a check on the speed of trains in two ways —the reports made by the guard and tho times at which every train is checked in and out of stations.

Trains were run at the ,best speed consistent with safety, said the official and that speed was further limited so as'not to cause discomfort to passengers. Safe speed varied according to the physical nature of the country traversed. In some places it was made very low owing to the possibility of slips. Short radius curves were another limit on speed and soft ground was a third. Over soft or swampy ground speed had to be kept down as fast running knocked the track about. In some places the permanent way was laid over ground that was slipping slowly all the time, and a swiftly travelling train would accelerate the slip.. Such a. place was just outside Greymouth. Maximum speeds on the New Zealand railways varied from six to 50 miles nn hour. Generally it was from thirtyfive to fifty. Although the maximum average allowed was 50 miles an hour, !hat did not mean that it was unsafe to go faster. A train had to have "something up its sleeve" to make up for stops at crossings and other delays. Asked what was the maximum 'safe speed attainable on the 3ft 6in gauge, Mr. Binsted said that there was none except what the condition of the track and of the rolling stock made. They could stand up only to a certain amount of vibration, but", if trains were specially designed, v it would be quite safe to travel one' hundred miles an hour on the 3ft 6in gauge as it now was to travel fifty miles an hour.