LMS Resignalling in Manchester, 1929

Mechanical signalboxes at Victoria and Exchange stations were replaced by powerboxes with Westinghouse Style K frames. The following text and pictures are from a booklet issued by Westinghouse.

POSSIBLY at no other railway centre in Great Britain is the passenger traffic problem more complex than at Victoria and Exchange Stations of the L. M. & S. Railway, where the old L. & N. W. and L. & Y. systems converge and become one. The area served is exceedingly wide, and there is a continual stream of business traffic from and to places as far afield as St. Annes, Lytham, and even the North Wales residential resorts, whilst, nearer in, Preston, Blackburn, Bolton, etc., contribute a large quota. Thereto must be added the heavy Blackpool and Southport excursion traffic, some trains passing through and others starting from and terminating at Manchester. Last, but not least, is the shunting of rolling-stock after the morning rush, to storage sidings, from whence it has to be collected again later on for the evening return journeys. A further complication, of course, is the very heavy goods traffic of this great industrial centre.

With the amalgamation on the 1st January, 1922, of the L. & N. W. Railway with the L. & Y. Railway, naturally one of the first matters to be considered was an improvement in the communication between the two systems. Hitherto there had been only one through road in either direction, used mainly for goods traffic, or for long-distance trains passing from one system to the other without stopping ; and, obviously, if full advantage were to be gained from the unification, considerable alterations would have to be made both to the stations themselves and to the permanent way. The public are already thoroughly familiar, from articles in the technical and daily press, with the remodelled joint station and its platform of over 2,000 feet long, and we do not propose to deal further with it. The alterations to the layout of the permanent way between and within the two stations come under a different category, owing to the necessity of reinforcing the signalling within the area directly affected thereby.

During the course of the investigation, many schemes came under consideration, and one serious difficulty with which the Railway Officers were faced was the fact that, if the existing mechanical signalling was to be retained, a number of new cabins would have to be installed to accommodate the additional levers required for the new traffic facilities. Taking into consideration the cost of these additions and the eventual heavy increase in the wages bill to man the new cabins, a decision was ultimately reached to remove the whole of the mechanical signalling concerned, and to replace it by a system of power operation.

At about the time that this problem was under consideration, the Signal Engineers of this country had appointed a Committee to advise whether there was any marked advantage in the use of 3-aspect signals. After long deliberations this Committee decided that, because of the complicated nature of the traffic that has to be handled in this country, particularly the admixture of suburban electric, fast passenger steam, and goods trains with unbraked vehicles, there was a marked advantage in adopting a system which would permit of the use not only of 3-aspect but also of 4-aspect signals. After the preparation of many schemes, including the use of 2-aspect and 3-aspect signals, the traffic officers of the L. M. & S. Railway came to a similar conclusion, and decided to adopt 4-aspect signalling for Manchester.

It was natural that the alterations to the tracks should be carried out by the Permanent Way Department, and, at first, the L. M. & S. Railway Company was disposed to undertake the whole of the alterations, including the resignalling, purchasing the requisite material from Signal Manufacturers. However, before coming to a final decision, they invited tenders for the resignalling, including installation; and after carefully studying all the tenders received and comparing them with their own estimates, they decided to entrust the work to The Westinghouse Brake and Saxby Signal Co., Ltd.

Advantages of Contract Work.

The advantage of the letting of a contract to a large signalling firm, with its drawing office, workshops, staff of engineers, erectors, etc., is that the work can progress in an orderly and systematic fashion. This avoids the confusion which must occur when material ordered by a Railway Company arrives either before or after the date on which it is required. Immediately the notification is given of the acceptance of a tender, it is possible to notify works to proceed with the preparation of the material; and the instructions are given in such order that the flow of material to the site is in the sequence required by the construction staff. This avoids the necessity for storage of a considerable quantity of material on the ground, with double handling, risk of damage, fire, etc., it being possible to deliver the bulk of the material directly on the site at which it has to be fixed. For instance, on the Manchester installation it was possible to start work on the interlocking frames almost immediately the order was received, and to commence their erection in readiness for the locking, which was designed by the Railway Company's engineers and forwarded later. Signals, point machines, relays, and other details could also be put in hand. In the meantime, meetings between the Contractors and the Railway Officials were arranged on the site for the purpose of settling details. These included the design of the signal cabins, which was in itself a difficult problem, owing to the very limited space available, the line being mainly built on viaducts. The photographs on page 9 show the neat way in which these have been arranged.

At the early meetings a problem of some difficulty had to be tackled — i.e., so to design the ground connections for the power point layouts that they would be adaptable to the varied types of switches and other permanent way existing on the site. It should be remembered that two main types of permanent way — namely, L. & Y. and L. & N. W. — already existed, while new work put in was to revised British Standard, and it was well known that all replacements in future would be of the latter type. While it was not possible to make every detail adaptable to the varying types, as each railway had used from time to time different patterns of switches, chairs, tie-plates, etc., a design was finally arrived at to connect to the R.B.S. type of permanent way, without the necessity of drilling any holes on the site, and yet which could be fitted to the old L. & Y. and L. & N. W. switch layouts with only minor alterations. Thus, in the event of these layouts being converted at any time to the British Standard, the apparatus supplied will be suitable. The photographs on pages 19 to 21 show the neat and simple design of this layout. This is of importance to the Railway Companies, not only because of the first cost of installation, but also because of the small amount of labour involved when renewals are necessary, such renewals generally calling of overtime on the part of the Signal Department's forces. As an illustration of the ease with which these layouts can be installed, the Contractors were able, without the necessity of bringing extra staff to the work, to fit and bring into operation some 50 pairs of points in one night. 

Meetings on the ground also determined the exact positions in which the signals were to be fixed, the Contractors providing templates and foundation bolts. The Railway Company was enabled to have the latter set in readiness for the arrival of the signals. Many of the foundations were pre-cast, and thus the necessity of hauling ballast, cement, and water to the site was avoided. It was not possible to do this in every instance, because in some cases walls, arches, and piers had to be interfered with.

A matter of considerable difficulty in railways built on viaducts and arches of this character is the installation of cables. The Contractors prepared plans showing the cables required to be run, and their routes ; and calculated the sizes of the trunking, etc.; and, directly the approval of the Railway Company was given, were able to commence the installation. Co-operation between the Railway Officials and the Contractors resulted in the preparation of designs of the most economical sizes in view of standard timber available (see page 24). In certain instances, where large runs of cable had to cross under tracks (see page 27), it was decided to instal fibre conduit in concrete with manholes at intervals. The conduit, manhole covers, and rims were supplied by the Contractors and installed to their drawings by the railway staff.

In order that a clear understanding of the magnitude of this undertaking can be obtained, a plan has been prepared, the upper portion of which shows the permanent way and signals as they existed prior to the alterations, the lower the completed work. This is inserted opposite page 28.

Crossover junctions have been laid in between the Slow South Lines and the Slow North Lines, and corresponding junctions between the Slow North Lines and the Slow South Lines. An advantage of these arrangements is that, whilst the North Lines continue to command all the platform lines in Victoria, they are also connected with all those in Exchange. Similarly, in addition to the South Lines having access to all the platforms in Exchange, they also serve all those in Victoria. As a consequence, trains can now leave Victoria for destinations served by the South Lines — e.g., North Wales, — and can depart from Exchange for all places in the North and West for which Victoria only was generally used. This is a great public convenience, as it saves many passengers having to transfer between the two stations.

It is now possible to close Exchange Station entirely, if desired — as, for instance, on Sundays.

The signal cabins are shown on both of these plans. Originally there were ten, with a total of 589 levers, whereas in the final scheme there are three power-worked cabins—Deal Street, Victoria West Junction, and Irwell Bridge Sidings, — and three mechanical boxes — Ordsall Lane, Salford, and Victoria East Junction. From these last a considerable number of mechanical levers have been removed, and the totals are now 188 power levers and 216 mechanical for the whole of the section shown on the plan. There is thus a saving of four signal cabins and 185 levers, notwithstanding which there are a considerably greater number of points and signals to be controlled than in the original scheme.

There has been effected altogether a saving in operating staff required of 11 signalmen, and it will be also appreciated that the communication between the shunters, platform staff, and other traffic officials with the signal cabin has been much simplified.  

Of course, it could have been arranged for all the power working to be operated from one central cabin, but a careful study of the conditions at Manchester showed that there are two main divisions of work, made necessary by the varied nature of the traffic which has to be dealt with. One of the chief characteristics of Victoria and Exchange Stations is that many local passenger trains start and terminate at one or other of them, requiring considerable marshalling just outside. Again, at certain times many classes of trains — other than through traffic — have to be speedily handled, also necessitating local communication between the shunters and the signal cabin.
For these, and other relatively minor, reasons, it was deemed advisable to divide the signalling also into two main areas, each with its own cabin, from which all local movements could be regulated, but with interccmmunication for through traffic.

A feature of some interest with the new arrangement is that at night time and on Sundays there is now no necessity to cross over trains from their ordinary running lines at Deal Street Signal Cabin. Arrangements have been made whereby, when the points are set for the straight lines and the signal levers reversed, the pulling of a switch-out lever converts the straight road signals on the North Lines into automatic working, with a consequent saving in operating staff.

Progress of Work.

The work was carried out in approximately the following order : —

(a) Installation of trunking and bonding of rails carried out simultaneously. At about this time the Railway Company commenced setting the foundations for the signals, and the building of the signal cabins.

(b) Delivery of signal posts commenced, and these were erected on arrival ; cable was run in the trunking already fixed.

(c) Point machines were received and fixed as and when the timbers on which they were to be fixed were installed by the Railway Company.

Trunking for the track connections was installed, and the wiring to the rails, as well as the jumpers, laid and connected up. At the same time the Railway Company installed the insulating rail joints.

(d) As soon as the signal cabins were ready, the power frames were delivered and erected, the locking installed and tested, and the teak cabinets for relays, transformers, and fuse housings, which were manufactured in the Contractors' works, were delivered to the site and erected. Relays and transformers had by this time arrived on the site and were installed in these cabins, and the work of wiring-up commenced.

(e) The installation of apparatus and the wiring up of all the outside fittings progressed continuously in such order as to allow the Contractors, soon after current was available, to commence testing individual pieces of apparatus, and afterwards to make exhaustive tests of the whole of the work prior to the completion of the Railway Company's own tests. These latter were carried out in sufficient time to enable the installation to be brought into service in time for the Easter holidays, when heavy traffic is always experienced at Manchester. It was necessary that this work should be completed by then, as between Easter and Whitsun, and subsequently during the summer, there is no slack period night or day.


After many consultations between traffic and engineering officials, it was decided that the new system of signalling should be brought into service in three sections, and on dates as near together as possible (successive week-ends), without interfering unduly with the traffic.


The first stage comprised the new signalling on the old L. & Y. section — that is, from Salford to Victoria on the Fast and Slow Line, section B. The second stage was the bringing into service of the signalling on the lines from Ordsall Lane up to and including Exchange Station, completing the remainder of the work at Deal Street Cabin, and a considerable portion of that at Victoria West. The third stage was held over for the rearrangement of the junction at Victoria West. Here a large amount of permanent way had to be altered, involving the removal of Victoria West Signal Cabin, as will be seen by comparison of the two plans. The signalling was brought into service within a few hours of the completion of the permanent-way work.

The whole of the work was carried out by the Contractors with the exception of minor details of preparing the foundations for signals and gantries, cutting away of brickwork, etc., which, in view of the construction of the line, was better carried out by the Railway Company.


The signal boxes, though built to suit the Contractors' apparatus, were designed by the Railway Company and erected by a local firm under the supervision of the Resident Engineer.


It is very interesting to note the neatness of the whole of the construction work and the absence from the track of point rods, signal detectors, etc. —obstacles which previously prevented easy walking thereon. This is of considerable advantage to the staff whose duties necessitate their presence on the lines.

The maintenance work is undertaken in three shifts, and requires only one linesman to be on duty at one time.


Installation in Service


The organisation agreed upon between the Railway Officials and the Contractors was successful in that all work was completed to schedule time. The specification called for the work to be carried out in not more than fifteen months. The contract was let in November, 1927, and the final opening took place in March, 1929, despite the severity of the weather conditions during the installation period. It is perhaps worthy of mentioning that the only delays which occurred subsequent to the change-over were attributable partly to the bad fogs experienced during that period, and partly to the difficulty the operating staff had in becoming conversant with the new conditions. This difficulty will be appreciated when it is understood that some thousands of drivers and other men from all parts of the country had to be conducted round the site before the new signals were brought into service, the traffic which enters Manchester coming from nearly every part of the L. M. & S. system.


Since its installation, the system has operated exceedingly satisfactorily, and under the most severe conditions. Trains are arriving and departing with promptitude, drivers finding that the visibility of the signals under all conditions, and the indications they display, enable them to run with much greater confidence than in the past.


Power Interlocking Frames.

There are three power interlocking frames—viz., at Deal Street, VictoriaWest, and Irwell Bridge .

          They are of our standard pattern, entirely encased in teak. Easy access for maintenance men is provided by means of a passage running right through the frames, so that all terminals, electric locks, contacts, mechanical locking, wireways, etc., can be readily inspected.


Electric Locking

All the most modern features of electric locking have been employed, this being made possible by the use of complete track circuits throughout the area concerned.


FIRSTLY—An illuminated diagram is provided in each of the main cabins, immediately informing the signalman of the position of any train under his control.


SECONDLY—All main signals are directly controlled by the track circuits over which they read, as well as constantly detected through all facing points on the route.


THIRDLY—By the use of approach and back locking of point levers, the route over which any signal reads is held during the passage of the train.


LASTLY—To provide maximum traffic facilities, sectional release locking has been employed. As is well known, this enables a fresh route to be set up at the earliest possible moment, only the points ahead of the train being held, while those in the rear become free immediately after the passage of the train. This special feature was adopted at Manchester owing to the very complicated nature of the traffic to be handled.


Many of the signals are approached locked, and automatic time releases are provided in many instances to give maximum traffic facilities without impairing the safety of the system.


Lever Arrangements.


In this installation there are 192 signals (exclusive of distant signals) reading over 299 different routes, which are controlled from 135 levers. The economy in signal levers has been accomplished by means of signal selection and the use of " push-pull " levers for many shunt signals, this being in accordance with the usual practice of the L. M. & S. Railway for power installations. The normal position of the "push-pull" lever is in the centre of the lever quadrant, the two reverse positions being " push " and " pull."


All aspects of signals and route indicators, as well as the positions "normal " and   reverse of points, are repeated above the corresponding levers by illuminated indications let into the front of the interlocking frame.


The circuit generally employed for signal indication purposes is the well-known series resistance " scheme, as originated by the Westinghouse Company, the special feature being the constant indication of any signal at any time without employing any apparatus having moving parts, the indications in the cabin being proportional to the brilliance of the light displayed by the signal itself.


Block Working.


Owing to the nature of the traffic and the complicated routing of the trains at Manchester , the Railway Company deemed it advisable to retain certain features of the block working. For this apparatus a special form of luminous block instrument was designed, which was incorporated in the interlocking frames. This instrument and its associated bell are worked from the A.C. supply through metal rectifiers.



There are 137 point layouts controlled by 130 point machines. These are the Westinghouse style M, and combine lock and detector in one unit. In a number of cases, such as double slips or complicated routes, it has been necessary to fit locks and detectors in the 4-foot way, using our standard style C point and lock detector. Constant detection of all points is provided by using 3-position A.C. Vane Point Detection Relays, which are immune to operation by D.C. The circuit employed is the Westinghouse standard polarised circuit, which is free from interference by extraneous currents, false feeds, or crosses in the circuits. The average time for the operation of a pair of points is 2\ seconds.


The point machines are operated by direct current, as this is more economical in an installation such as this arrangement. Hitherto, one of the disadvantages of D.C. operation has been the use of large batteries, which require expensive and complicated charging arrangements- By employing the Westinghouse Metal Rectifier, this disadvantage has been overcome at Manchester, the supply for the points being taken direct from the 3-phase supply mains through the rectifiers to the D.C. busbars. Duplicate rectifiers are provided, each having a capacity of 3 k.v.a. (see page 26), thus ensuring ample margin for the maximum number of point machines which can be thrown at one time.


The track-circuited area extends from Ordsall Lane and Salford to Victoria East, and required the installation of 179 track circuits. The track circuits are of the condenser-fed type, a condenser being connected direct in one leg of the feed circuits. The relays are of the double-element vane type. With very few exceptions, both track-feed transformers, condensers, and relays are housed in the cabins. The track-circuit cables are brought to terminals located at the ends of the relay racks, and the wiring from these terminals to the apparatus is carried out with wire insulated with "Maconite" and covered with a "flame-proof" braid. An examination of the photographs will show the neatness of the arrangements and of the wiring. This method of installation has considerable advantages, dispensing as it does with the many apparatus cases that would otherwise be required, while there is practically no need for a linesman to leave the cabin to adjust track circuits.


The signal control and point indication relays are also located in racks, with similar terminal and wiring arrangements. The relay racks are located in the lower sections of the cabins immediately below the interlocking frames. This arrangement reduces the wiring required to the minimum. The total number of relays of various types furnished for this installation was 826.


All the cable used on this contract, equivalent to 334 miles of conductor, was "Maconite" insulated, the dielectric thicknesses and tests being to British Engineering Standards Association Spec. No. 7 for 660-volt cables. Multi-core cables were used wherever possible, suitable size core cables being used for each individual function. In other words, separate cored cables were taken from the signal cabin to each piece of apparatus. This course is usual with modern installations, and obviates the great amount of terminating which is required when large multi-core cables are used, with disconnection boxes situated round the interlocking. For internal wiring, such as for cabins, single conductor cables were employed, covered overall with a flame-proof braiding.

Track diagram, Ordsall Lane and Salford area

Track diagram, Exchange area

Track diagram, Victoria area

Special Notice



Sidan uppdaterad den 5 juni 2008