Railroad Gazette/Volume 38/Number 5/Automatic Block Signals
Automatic Block Signals in Europe.
The report made by Mr. C. H. Platt for the International Railway Congress on automatic block signals was noted in the Railroad Gazette of Nov. 11, 1904. The report on this subject for all countries except America is by Mr. Margot, of the Paris-Lyons-Mediterranean, and it is printed in the last number of the Bulletin of the Congress, page 1613. In 1899 the P.-L.-M. had 24 miles equipped with automatic signals; since then, automatics have been erected on the Midi, of France, 26 miles; on the London & South Western, six miles; on the North Eastern of England, 10 miles; and on the Austrian Southern, nine miles. Comparing this short list (74 miles, including 26 miles additional on the P.-L.-M.) with the automatic signaling of America, the reporter devotes his chief attention to the question why other countries do not follow the American example.
Discussing experience in Europe, Mr. Margot finds that the locomotive runners accommodate themselves readily to the Hall enclosed disks. There has been no trouble as yet from the accumulation of snow or frost on the glass windows of the signal cases. Answering criticisms which were made at the 1900 Congress, he says that wooden fish-plates have done well on the Midi, and that “the track circuit is no obstacle to the construction of very solid track.” The Hall signals on the P.-L.-M. were installed in 1898, but not for two years did they trust them. Finally, in August, 1900, the old manual signals were put out of service, and the automatics allowed to serve. For the first 16 months there were 365 non-dangerous failures and 17 dangerous; but the similar and more perfect installation on the Midi showed, for eight months, 129 failures, equal to 63 per 100,000 operations, none of which were dangerous.
The automatic signals on the Austrian Southern were made by an electric company of Budapest, and the same road is going to try another system invented in Vienna. On the Paris Metropolitan there are automatic signals worked by track instruments, without a track circuit. The Dutch State Railroads have 249 miles of line equipped with non-automatic signals; there are 128 cabins, of which all but four are attended by station men, gate keepers, etc., who would have to be employed anyway.
The arguments concerning the relative merits of automatic and non-automatic block signals are set forth at considerable length. An officer of the P.-L.-M. in a statement favoring manual signaling, says that at 36 signal stations, where the number of trains per day is 80, the signalmen in one year (1901) stopped 97 trains on account of defects or difficulties in the cars, or their appurtenances, things which, of course, the automatics could not do. All of the different roads replying to the reporter’s circular emphasized this feature—the desirability of having watchmen on duty to perform other duties than block signaling. Most of the roads give as a principal reason for not adopting an automatic system, the fact that they have men stationed at frequent intervals along the line who can manage the manual signals without much additional expense.
The Kaiser Ferdinand-Northern Railroad has 172 miles of line equipped with the manual block system; the Hungarian State Railroad, 262 miles; the Belgian State Railroad, 1,015 miles, and the Orleans of France has 932 miles.
The South-Eastern & Chatham, of England, expresses a favorable opinion of automatic block signals, but has not adopted them. The Lancashire & Yorkshire, of England, and the Cape Government Railroads of South Africa are going to try the “American block system.”
Mr. Margot concludes that lines already equipped with non-automatic signals will find no advantage in changing to automatics, except in special cases, as, for example, where an intermediate section is required in a long tunnel, or elsewhere. But on lines not yet fitted with a block system it may be advantageous to adopt the automatic. The automatic is without doubt best suited to metropolitan lines and under certain conditions “to lines on which it is desired to increase safety without excessively increasing the working expenses.”
His two principal final conclusions are:
1. The automatic block system, using a track circuit which substitutes the intervention of the train for human agency, satisfies most completely the conditions of working, from the technical point of view.
2. The automatic block has not yet attained any development outside the United States of America. Nevertheless, some applications made on main lines are, at present time, beyond the experimental stage. It has been observed, more particularly, that the track circuit is compatible with high speeds, without entailing appreciable difficulty in the maintenance of the track.