February 1906, No. 96 The Railway and Marine World (Toronto) Page 79, col. 2

St. Clair tunnel electrification

The single-phase electric locomotive adopted by the St. Clair Tunnel Co. for the operation of the St. Clair tunnel, which connects the Middle and Western divisions of the G.T.R., will weigh approximately 62 tons, and will develop a draw-bar pull of 25,000 lbs. on a 2 per cent, grade at a speed of 10 miles an hour. It is of the rigid frame type with driving axle boxes held in the same frame that contains the draft gear. It will be mounted on three pairs of driving wheels, which will sustain the entire weight, distributed by equalizer bars similar to those used in steam locomotive practice, will have an outside frame supported on semi-elliptical springs, and will be equipped with Westinghouse friction draft gear, MCB automatic couplings, air sanding apparatus, and bumper steps, front and back. The cab will be of sheet steel mounted on a framework of iron which supports both walls and roof. The principal dimensions will be approximately as follows: Length over end sills, 27 ft. 9 in.; rigid wheel base, 12 ft.; width over all, 9 1/2 ft.; height from top of rail to top of cab, 12 1/2 ft.; diameter of driving wheels, 62 in.

The operating apparatus will be arranged along the sides of the cab, leaving a free passage-way ft. wide the entire length. The cab will be lighted and heated by electricity, arrangement being made to screen the instrument lights while the locomotive is running. Westinghouse combination automatic and straight air and American driver brakes will be used. The air supply will be provided by a two-cylinder motor-driven air compressor having, with a 5 in. stroke and speed of 190 r.p.m., a capacity of 45 cub. ft. of air per minute. Air reservoirs, signal outfits, whistle, bell with pneumatic ringers, automatic pump governor, tools, instruments, gauges, headlights, push poles and other details complete the auxiliary equipment.

A motor will be geared to each axle, giving each unit an aggregate rated capacity of 750 h.p. They will be of the Westinghouse single-phase alternating-current, series wound, compensating type, and of the same general character as the motors selected by the New York, New Haven and Hartford Rd. for the operation of its line between New Haven and New York. Each motor will weigh complete approximately 14,500 lbs., the armature weighing approximately 5,600 lbs. The motor frame will consist of a steel cylinder cast in one piece and enclosed at the end by brackets of the same material, which carry the bearings and oil reservoirs. The suspension noses and safety lugs will form a part of the main casting. Seats for the axle bearings will be cast solid with the frame. All bearings will be of phosphorbronze lined with babbitt and divided into two parts. They will be of exceptionally large dimensions, will be arranged for oil waste lubrication, and will be provided with large openings on the low pressure side, giving a thorough lubrication to the entire bearing surface. Oil will be fed into the reservoirs through openings separate from the waste pockets and will therefore reach the waste from below and be thoroughly filtered before entering the bearing. The motors will be swung between the locomotive frame and the driving axles by a flexible nose suspension from two hangers supported by a truck transom, and passing through heavy lugs with helical springs above and below the lug. The motors will be held to the axle by means of caps split at an angle of 35 deg. with the perpendicular, so that the greater part of the weight will be borne by solid projections from the motor frame, which will extend over the axle, rather than by the cap bolts. Large openings above and below will provide access to the commutator and brush holders.

General map and profile of yards and St. Clair tunnel, G.T.R.

Within the cylinder of the motor frame there will be built up a core of soft steel punchings, forming a complete laminated field. The punchings will be dovetailed into the frame and clamped between end rings of cast steel. The field coils will be wound with copper strap insulated between turns and about the coils by mica, and finished by taping and dipping, and will be impregnated in the best grade of varnishes, providing a sealed coil which can withstand the most severe internal heat and be practically indestructible under the usual conditions of heavy railway service. In addition to the main coils the field will carry a neutralizing winding consisting of copper bars placed in slots in the pole faces and joined at the ends by connectors of copper strap, so as to form one continuous winding, which will be connected in series with the main field winding and with the armature circuit. The magnetizing effect of this auxiliary winding will be directly opposite to and neutralizes that of the armature winding, thus eliminating the effect of armature re-action and improving commutation and power factor. The main coils will be easily removable without disturbing the auxiliary winding. The armature cores will be formed of slotted soft steel punchings built up upon a spider and keyed in place. The spider will be forced upon the shaft with heavy pressure and secured by a steel key. Coils of copper strap will be embedded in the slots and joined to form a closed multi-circuit winding which will be cross-connected, like the multi-circuit winding of a direct-current generator. The basis of the insulation will be mica. A preventive winding will be connected between the commutator and the main coils, introducing a preventive action which will be effective only when the coil is passing under the brush.

During operation a forced circulation of air supplied by motor-driven blowers will enter at the rear, distribute itself thoroughly throughout the motor and escape through the perforated cover over the commutator. This system of forced ventilation of both motors and auxiliary apparatus forms one of the most interesting innovations in electric railway construction. It secures a maximum output from a given weight of material, and a high ratio of continuous output to the one-hour motor rating common in railway practice. It also provides effective ventilation while the locomotive is not in operation as the blower may be driven while the locomotive is standing at the station or at the end of the line. Motors ventilated in this manner are enclosed and are thereby protected form internal damage by dirt and water and from mechanical injury. These motors are wound for 240 volts and 25 cycles per second, and have a nominal rating of 250 h.p. each, on the basis of usual electric railway practice.

Diagram feeder system for the St. Clair tunnel transmission.

The essential elements of the control equipment will include the collecting devices, the auto-transformers, the unit switches, the preventive coils, the reverser and master controllers. A multi-unit system of control will be provided with pneumatically operated switches and circuit breakers, low voltage control circuit, and other characteristics standard in Westinghouse practice. Any unit will be controllable from either end, and two or more units may be coupled together and operated from a single cab and by a single crew. The tractive effort which can be readily applied to a single train will therefore be limited only by the number of units available, and the hauling power will be limited only by the mechanical strength of the coupling between locomotive and cars. A control circuit will be carried from one unit to the next by means of connecting sockets and jumpers in the usual manner. Speed control of the driving motors will be secured by variation of the voltage at the motors obtained by means of taps taken from the winding of the auto-transformer, which will receive current from the trolley at 3,000 volts and reduce it to 240 volts or lower, according to the tap employed. These taps will be connected to unit switches from which current will be led through the preventive coils to the motors. Four unit switches will serve to reverse the field of each motor.

The unit switches will be of standard Westinghouse design and will, in effect, be pneumatically operated circuit breakers of great power and reliability. The mechanism will be such that a rolling and sliding contact will be obtained when the switch closes and opens. The arc will be broken at the taps, leaving the contact surfaces smooth and unscarred. Each unit will have a magnetic blow-out coil with laminated core. The switch cylinders will be controlled by magnetically operated valves, current for which will be obtained from a 50-volt tap from the auto-transformer. The sequence of operation will be governed by the master controller in conjunction with a system of inter-locks which will prevent short circuit of the steps between taps from the auto-transformer or improper operation of the controlling mechanism. At any running point four controlling switches will be closed. Through the preventive coils approximately the same amount of current will be drawn from each of these switches and the leads to which they are connected. To change to a higher voltage on the motors, the master controller is moved to the next notch, opening the last switch of the group that is closed and closing the switch next higher, with the result that the motor voltage is shifted up one step. By this arrangement the voltage at the motor will be completely under control of the locomotive driver and may be varied up and down at will without opening more than one-quarter of the load current. Small switches in the circuits to the magnets of the reversing switches will enable any motor or combination of motors to be cut out without disturbing the others. Every one of the 17 controlling connections will provide an efficient running point. This number will be ample to prevent any slipping of the driving wheels due to increase of current from one notch to another. Whether empty or heavily loaded, operated in single or multiple units, torque and draw-bar pull may be gradually applied and the locomotive started without jar.

Section of St. Clair tunnel.

Each locomotive unit will be equipped with a pneumatically operated pantagraph trolley to collect current from the overhead lines outside the tunnel and throughout the yards. The proportions of the pantagraph will be such that, when extended, it will make contact with the trolley wire 22 ft. above the rail, and, when closed down, the contact shoe will not extend more than 18 in. above the roof of the locomotive. The pantagraph will have a broad base and will be constructed of light and stiff material. A no. 0000 grooved overhead trolley wire will be suspended from a single ?? inch, high strength, double galvanized, steel strand, messenger cable by hangers of varying length in such a manner that the trolley wire will be approximately horizontal. The messenger cable will be swung from structural iron bridges located throughout the yards, and of suitable length to span the proper number of tracks. There will also be a small section of track equipped with a trolley line swung by catenary suspension from bracket arms supported on lattice-work poles.

For the operation of the electric locomotives a complete power plant will be installed by the St. Clair Tunnel Co., including two 1,250 kw., 3,300 volts, 3-phase, 25 cycle, 1,500 r.p.m., rotating field, Westinghouse steam turbine units with the necessary complement of switchboards, exciters, lightning protective apparatus, etc. This station will also supply current to light the buildings, yards and tunnel, to operate motor-driven centrifugal and triplex pumps which drain the tunnel and approaches and operate the sewage system, to run motors in the roundhouses and for other purposes.

The new equipment will handle that portion of the G.T.R. which connects the divisions terminating at Sarnia, Ont., and Port Huron, Mich., on opposite sides of the St. Clair river. The tunnel proper is 6,032 ft. long, and the line to be electrically operated measures 19,348 ft. from terminal to terminal. A pair of the new units will be capable of hauling a 1,000 ton train through the tunnel without division. Mechanical consideration limit the advisable weight of train in the tunnel to these figures. Heavier trains can be divided or sent through together with locomotives in front and behind. The service requires that each unit shall take a train of 500 tons through the tunnel block from summit to summit in 15 minutes, under the following conditions: It will be coupled to the train on a level track 1,200 ft. from the summit, and must accelerate it up to a speed of 12 miles an hour in two minutes, at the end of which time it will have reached the summit of the gradient leading down into the tunnel. It will then run down a gradient of 2 per cent, to the level track in the tunnel at a speed not exceeding 25 miles an hour, continue on the practically level stretch under the river, and then draw the train up a 2 per cent gradient at the rate of 10 miles an hour to the level track beyond the tunnel approach on the other side. It must then gradually accelerate the train until a speed of 18 miles an hour is reached. Each unit must be capable of exerting a tractive effort of 25,000 lbs. for a period of 5 minutes in addition to the energy required to accelerate the train at the starting point and to run with it into the terminal yard, from which point it must immediately run back to a position 1,200 ft. from the summit, couple to another train and be ready to start through the tunnel in the opposite direction. It must, therefore, make a run of the character described every 30 minutes.

Six of these locomotives are to be furnished by the Westinghouse Co. It is expected that the electric equipment will greatly relieve the traffic congestion now existing, and due in a large measure to the necessity of dividing trains at the terminal points, and to greatly simplify the operation of the road. Its opening will mark the progress of electrical methods in the railway field under conditions which seem peculiarly fitted to demonstrate its practical advantages in heavy service. That the single-phase system has been adopted for so important an undertaking makes evident the recognition accorded the alternating current by railway engineers, and indicates that its claims have been verified by the service already rendered.

The work of installation will be conducted under the supervision of B. J. Arnold, of Chicago, Consulting Engineer for the Tunnel Company, by whom the plans and specifications were prepared. The contract for the entire equipment was placed through the Canadian Westinghouse Co., Limited, of Hamilton, Ont. A large part of the apparatus will be constructed in its Hamilton works, and various Westinghouse interests will co-operate to complete the work.

The cuts illustrating this article are reproduced from the Railway and Engineering Review.

Railways: G.T.Ry.

Stations: Sarnia

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