Illustration of full size Working Apparatus. Gold Medals Paris Universal Exhibition 1878, and Barcelona 1888

This Apparatus is now on view at the works at Kilburn, and the efficient working of it may be tested practically.



The inquiries into the accidents of the past year speak very conclusively in favour of an early completion of the Absolute Block System of working on all Passenger Railways, and that that system should be supplemented by some means for preventing mistakes of Signalmen, which so often occur, and which in the present and previous years have led to very disastrous collisions, as at Canonbury. In this matter a report has been received from the Chief Inspector of his inspection, at the request of the London Brighton and South Coast Railway Company, of a means of accomplishing this object which has been put down as an experiment on a part of their railway. Colonel Yolland reports as follows:—

 Sir,                                                                                                                                                                                         24th- August, 1881.

" I have the honour to report, for the Information of the Board of Trade, that, in compliance with the instructions contained in your minute of the 9th instant, I have inspected  the union of the Lock and Block system (Hodgson's patent) which has been laid down by the London Brighton and South Coast Railway Company on a portion of their new Tunbridge Wells and Eastbourne Line, viz., at Heathfield, Horeham, Hellingly and Hailsham Stations. There are loop lines or passing places at all these stations except at Hellingly, where there is  no loop line, but the new line, except at the stations indicated, is a single line of  railway.

One of the principal alterations introduced by Messrs. Saxby and Farmer in the recent Improvements of the Lock and Block apparatus has been the introduction of a treadle near  each signal box, electrically connected with the telegraph instruments in the signal boxes at the stations, rendering it necessary in the working of the Block system that the actual running of each train should exercise a most important control over the signalmen in the signal Boxes. Thus, on the wheels of an arriving train passing over the treadle, whioh may be placed in advance of or some distance beyond the signal box, permission is thus given to the signalman in that box that he may give back ' Line clear' by the telegraph instrument  to the station from which the train has arrived, and thus telling the signalman there that the line between the two signal boxes Is clear of the train whioh he had last despatched, and  was ready for another train to proceed.

You are aware that the idea of making a train contribute to the safety of the public travelling on railways by telegraphing its own arrival at stated points, is by no means new,  and has long been advocated by the inspecting officers of the Board of Trade, and sundry experiments have been made to carry it into effect with success, but this has hitherto, as ar as I am aware, been found impracticable from the liability of the treadles to get out of order or to be destroyed altogether by the repeated blows reoeived from the wheels of a train in rapid motion. This objection has now, I think, been satisfactorily got rid of in this system, by making the deflection of the rail Itself, acting upon the short arm of a lever always in contact with the underside of the rail, the means of making an eleotrical contact through the long arm of the same lever with the telegraph instruments in the signal boxes. This electrical connexion with the telegraph instruments in the signal box takes off a look that prevents the signalman from moving the handles by whioh the signal 'Line clear' is transmitted.

This part of the apparatus is only likely to fail from the power of the battery not being properly maintained, or from carelessness on the part of the platelayers in disturbing the treadle which is placed between the rails in the four-foot space, and if out of order, must at once become apparent to the signalman in the adjacent signal box.

Another important alteration consists in the introduction of the ' electric slot,' by which the starting signals at one station are controlled from the next station in advance, so that | it is rendered impossible for the signalman at a station to lower the out-of-door 'starting signal'  for a train to leave that station until he has received ' Line clear'  from the next station or signal box in advance; and as soon as a train has been started and signalled to the station or signal box in advance, and is acknowledged by the signalman in advance sending back 'Line blocke' on the telegraph instrument,' the starting signal' is simultaneously, and by the same act of sending 'Line blocked,' again put to 'danger.'   This is not optional, but compulsory. as the very act of pressing in the plunger puts the starting signal at the rear station to 'danger.'

The arrangments by which, hitherto, a single signalman might at any time make a mistake, and give back 'Line clear' when it is not clear, or send on a train through a mistake in signalling when it should not have been sent on, are altogether changed.   The assent of two men is by this system required to make a mistake, and this is coupled with the further security obtained from the train itself virtually telegraphing its  own arrival at the advanced station or signal box, so that I do not see how, if this system be adopted and is faithfully carried out, a collision between folloving trains can take place. 



Attention is invited to this invention for uniting the working of the Block and Interlocking systems -- making them absolutely INTERDEPENDANT, and obviating the possible danger hitherto existing of contradiction between the BLOCK TELEGRAPH INDICATIONS transmitted from one station to another, and the Out-door Signals exhibited to Engine Drivers.

The invention carries the security of the Interlocking of Point and Out-Door Signal Levers a step further, it combines in one and the same apparatus those Levers, and also the Handles of the Train Telegraph Instruments. The Levers and the handles being interlocked reciprocally, with the result that there cannot be any contradictory working between the Out-door Signals and Points, NOR  BETWEEN THE OUT-DOOR SIGNALS AND POINTS, AND THE TRAIN TELEGRAPH  SIGNALS  TRANSMITTED ELECTRICALLY.

When it is considered that after all, whether in respect of the Block System or the Interlocking System, or both, it is upon the correct working of the Out-door Signals, and their due observance by the engine drivers, that the whole safety of Railway traffic depends, it would be difficult to over-estimate the importance of the object of securing as absolutely as possible the correct working of the Out-door Signals.
The illustration ----- shews a machine in which is contained an Interlocking Apparatus of 7 Levers for working Points and Signals, and 2 Improved Block Telegraph Instruments, for the exchange of Train Telegraph Signals with the Stations on either side, for Up and Down lines respectively. The Handles of the Block Instruments and the Point and Signal. levers being combined in one and the same Interlocking Mechanism, they cannot be manipulated in a contradictory manner.

The Block telegraph Instruments shewn in the drawing are of improved construction, simple, efficient and strong, one line wire only is required for the Signals for both Up and Down lines, and for the bells in both directions. The Locking Handles are attached to hollow spindles, in the centre of which are the spring commutator plungers.                              

When the Handles are moved to the right (which is the position of "Line Clear ") they work interlocking gear so as to Interlock the Point and Signal Levers in any pre-arranged manner as may be necessary to suit traffic requirements.   When the Handles are moved back to the 'Line Blocked' position, they are stopped in mid-stroke and become firmly locked, so that they cannot be moved again to the right for the purpose of giving 'Line Clear'  for a second Train, neither can they be placed in their normal position so as to unlock the Point and Signal Levers until the approaching Train has arrived and passed over the Treadle Apparatus shewn in the illustration.

On passing over the treadle the weight of the train deflects the rail and presses down the short end of a lever which is pivotted in a cast-iron box fixed to the sleepers; as this short end descends the long end rises and completes the electrical circuit, so that a current of electricity is sent through the Magnet of the Block Instrument, Unlocking the Handle which can then either) he restored to its normal position to unlock the Point and Signal Levers, or it can be again moved to the right to give 'Line Clear' for another Train.   See also Improved Rail Contact Maker, page 33.

The  arrangement  of   this   Treadle  and   its   action will be readily understood from the illustration.  It will be seen that it satisfactorily gets rid of the difficulty usually experienced with Treadles acted upon by passing trains, viz::- their liability to get out of order or be destroyed by the violent blows received from the wheels of Trains in rapid motion.  The short  ends of the Treadle Lever being always in contact with the underside of the rail, the wear and tear is reduced to a minimum, and consequent upon the relative proportions of the short and long end of the Lever, a very  slight deflection of the Rail gives  quite sufficient movement for insuring satisfactory electrical contact.

The improved instrument may be used  in   connection   with  any type of  Leverlocking   Apparatus,   and   may be used the Treadle as above described or not. When the Out-door Semaphore Signals are controlled by the Electric Slot Apparatus, shewn and described, page 18, 36 & 37, the plungers of the Block Instruments, on being pressed in, act upon the ELECTRIC SLOT APPARATUS as well as upon the Miniature Semaphore Arms of the Block Instrument at the next station, and the combination thus effected constitutes the Simplest and Most Perfect Block System in Existence.


The Starting Signals being controlled from the next Station in advance a signal for a train to proceed can not be given until 'Line Clear' has been received on the telegraph instrument; as seen as a train enters a section the signal is put to 'danger' and cannot be again lowered unitl the train has come out of the section at the other end, when it passes over a Tradle, which releases the instrument there, neither can the signal for the opposite direction be lowered whilst a train is in the section.   


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