CNR cuts costs with interlockings and CTC
Canadian National recently completed the first step toward consolidated interlocking and traffic control on one of Canada's heaviest traveled routes—30 miles of double-track between Toronto and Hamilton, Ont. At a cost of $580,000, the CN consolidated two mechanical, one remote and three new interlockings, switches and signals of which were previously controlled by switch tenders. Savings of over $44,000 annually in operating expenses are anticipated from the new terminal interlocking at Hamilton, Ont.
The new interlocking is controlled from a panel-type machine at Hamilton passenger station. Additional panels can be accommodated for the two other steps in the Toronto-Hamilton signaling project: (1) Three high-speed interlockings at Oakville, midway between Hamilton-Toronto, now under construction; and (2) a traffic control system on double-track to provide either-direction running on each track by signal indication. Thus, the traffic supervisor at Hamilton will control the Hamilton-Toronto mainline and Hamilton interlocking from one machine.
This new interlocking is concentrated in an area about three miles long. Double track extends west from Bayview through North Yard Lead interlocking to the Middle Switches. From the Middle Switches single track mainline runs through Hamilton passenger station to N&NW Junction, where the mainline reverts to double track east towards Niagara Falls. The line between the Middle Switches and N&NW Junction was originally a double-track mainline. As a result of the new signaling, one track was released for yard operation. From Bayview, a double-track line runs west to Hamilton West, and on to London and Sarnia. The third leg of the wye is a single-track line from Hamilton West east to Hamilton Junction, where it meets the Bayview double-track line going toward Hamilton passenger station. Hamilton Junction is also the connection with the Canadian Pacific, this being a double-track line to Hamilton.
This interlocking area handles the heaviest mainline traffic in Canada, with an average of 52 passenger and 37 through freight trains (both CNR and CPR) by Bayview daily. This includes an average of 10 freight and 8 passenger trains of the CP operated over CNR tracks between Toronto and Hamilton Junction, at which point they go on to their own tracks. Two CPR freight trains operate through Hamilton Junction between Hamilton and Guelph Junction. Through manifest freights of the CNR pick up and set off cars at Hamilton. In addition to the scheduled daily trains, the interlocking also handling switchers serving industrial tracks, helper engines, way freights, and work trains.
Bayview interlocking, formerly a mechanical plant, is remotely controlled from Hamilton.
A breakdown of train movements through each interlocking is as follows: Bayview, 120; Hamilton West, 50; Hamilton Junction, 90; North Yard Lead, 84; Middle Switches, 200 (this includes moves by yard and road engines to and from the shops, and crossover moves between the North and South Yards); N&NW Junction, 70. This is a total of 614 moves every 24 hours.
Adding to the traffic problem is the fact that Hamilton Terminal is off the main Toronto-London-Chicago and Toronto-London-Detroit routes. This means Toronto passenger trains bound for London must head in and back out to Bayview before proceeding to Hamilton West. London passenger trains bound for Toronto-Montréal proceed from Hamilton West to Bayview, and back in to Hamilton passenger station before heading out and proceeding to Toronto. All these passenger trains follow this procedure, with the exception of two eastward and one westward daily trains which bypass Hamilton and make their station stops in the suburbs. Four passenger trains, in addition to freight traffic, operate daily in both directions between Hamilton, Niagara Falls and Suspension Bridge. On the Hagersville subdivision between Hamilton and Jarvis, only extra trains are operated at the present time.
Panel control machine, in Hamilton passenger station will have a right wing to handle CTC between Hamilton and Toronto. Signals cleared by "push" or "turn" buttons. Switch levers at bottom of panel are "turned". Switches and signals at N&NW Jct. and Middle Switches are direct wire remote control, the rest are remotely controlled by Syncroscan.
Code system introduced by General Railway Signal in 1955[Railway Age, 1955-02-07 138(6), p. 10].
Hamilton is the hub of several Canadian National lines that serve this industrial city of 225,000 population. The double-track CN mainline between Hamilton and Toronto also handles Canadian Pacific trains. High speed interlockings are under construction at Oakville.
Terminal interlocking at Hamilton handles an average of 52 passenger and 37 freight trains daily. Turnouts are No. 28 [this is not correct], which are good for 28 mph. Speed is restricted to 20 mph Hamilton West to Bayview (descending 1 per cent grade), and elsewhere in the plant to 35 mph.
Originally, a movable point frog, crossovers and three single switches and associated interlocked home signals at Bayview, were controlled from a 24-lever mechanical interlocking machine. This mechanical plant required extensive repair, hence was due for replacement. Also, signaling had to be changed so the aspects displayed would agree with the new Uniform Code of Operating Rules in Canada. The rules require Canadian railroads to change from previous route signaling to speed signaling.
A table interlocker in the Bayview tower controlled the single switch, crossover and searchlight signals at Hamilton West. The movable point frog, two crossovers, four single switches and associated signals at Hamilton Junction, were controlled from a 48-lever mechanical interlocking machine owned by the Canadian Pacific. The switch at North Yard Lead was formerly hand-thrown, operated by switch tenders who gave hand signals for directing train movements.
At the Middle Switches are three crossovers and a single power switch, formerly all hand-thrown by switch tenders. The crossover and new single switch with associated signals at N&NW Junction, east of the Hamilton passenger station, were formerly operated by switch tenders. A rearrangement of track was made at the N&NW Junction and Bayview to improve the layout, the single switch at N&NW Junction formerly being part of a scissors crossover, and switches 213 and 217 at Bayview previously forming part of a movable point frog.
Switches and signals at N&NW Junction and the Middle Switches are direct wire control. North Yard Lead, Hamilton Junction, Hamilton West and Bayview interlockings are remote controlled by the GRS Syncroscan system.
The new CNR interlocking has these three special features
Call-on used for closing up
For closing up trains entering the yard or passenger station, signals can be controlled to display the call-on aspect. This aspect is yellow for a dwarf signal and red-over-yellow for a high signal. The call-on aspect is used also for directing train moves against the normal current of traffic in those positions of the interlocking having two main tracks.
Call-on signals cleared in the normal direction of traffic are progressive and cannot be cleared indiscriminantly. The block and approach track must be occupied before the signal will clear. If the block becomes unoccupied before the call-on is accepted, the signal will progress or climb to a less restrictive aspect. When clearing call-ons against the current of traffic the block is not required, and the signal aspect remains red-over-yellow or yellow.
Single track is signaled for double direction running and is circuited to give the equivalent of traffic locking. That is, opposing call-on are not allowed to clear, nor can traffic direction be changed with a train in the block. Call-on aspects are used only for following moves.
Double track is signaled for single-direction normal right-hand running. Trains can be routed against this normal direction of traffic by signal indication. However, only call-on aspects are provided in this direction. Call-on aspects cleared against the normal direction of traffic in double track territory are non-interlocked, in that a call-on can also be cleared with current of traffic into the one previously cleared. Circuits provide, however, that when a call-on is initiated against the normal direction, the "H" circuit to the adjacent plant is de-energized and a time interval runs before the call-on will clear. These call-on aspects against the direction of traffic provide for coupling-on movements. For example, helper engines at Bayview back on to westward freights to assist them up a one per cent grade toward Hamilton West and on to London. Other moves where call-on aspects are used are for car transfer movements at Hamilton Junction, between the CNR and CPR; and also for switching movements at North Yard Lead and the Middle Switches.
Timing circuits for locks
All main-track hand-throw switches are equipped with electric locks, with the exception of the short spur track at Hamilton West, into which trains do not normally clear. Where a crossover is the mainline, the mainline switch is electrically locked with the opposite switch, being bolt-locked by a pipe connection. All locks are lever controlled for supervisory control by the traffic supervisor.
For a movement from the main track to a siding or yard track, the lock release cannot be sent out while a signal is cleared into the block, because with a release given only a call-on signal is allowed. Therefore, a lock release going out after the signal was cleared would cancel the signal. A lock release can be sent out, however, after the block becomes occupied. With the release given and the block occupied for time, the electric lock in the field may be released. This time is sufficient for the train to have reached the switch, thus obviating need for the short release track.
If the release is sent out before the signal is cleared, only a call-on signal is allowed.
When entering the mainline from a siding or yard track through an electrically locked switch, no special time is involved other than the usual time equivalent to that for approach locking. Signals governing into the route must have been at Stop for a predetermined time interval. Of course, the main line track circuit timed-up would also allow the lock to be released. Lock L61 is the exception to this rule because it is within interlocking limits. Time locking is used throughout with two-track release.
Special clearing for switching moves
To facilitate switching moves over the South Yard lead near the yardmaster's office at Middle Switches, a special control is provided on signals 128 and 130, in addition to the usual control. Normally, signal 128 will clear to yellow when the signal knob is pushed, and will cancel when the train passes the signal. By rotating the 128 knob, both 128 and 130 will clear to yellow, the aspects remaining displayed until canceled from the control machine. This unique control allows switching moves on the switching lead in both directions with the switch normal, without attention by the traffic supervisor. These signals are sometimes left cleared for long periods of time while switching is taking place. This allows the traffic supervisor to ignore the signals unless the trainman calls in for the switch to be thrown reverse.