J. and H. McLaren: Road Locomotive
Note: This is a sub-section of J. and H. McLaren
Extract from Steam Locomotion on Common Roads by William Fletcher. Published 1891.
Messrs. J. and H. McLaren, of the Midland Engine Works, Leeds, have only been established about 14 years, but in this brief time they have made for themselves a well-earned reputation in the road locomotive business. These eminent engineers have made the latest, and probably the best high speed traction engine ever constructed.
In 1885 one engine was built for passenger service in India, which is illustrated by Fig. 101. We quote a few particulars from The Engineer-, "This engine was of the compound type, and fitted with the well-known spring wheels. It was designed for running at eight miles an hour while hauling a load of 2.5 tons. Some difficulty was experienced in finding a piece of road suitable for the test, near the works at Leeds.
The shell of the boiler, which was of the ordinary locomotive construction, was made of steel, and the fire-box of Farnley iron, intended for a working pressure of 150 lbs. per square in. The cylinders were 6.5in. and 10 in. diameter, and both of them 12 in. stroke. The crankshaft was 3.5 in. diameter, and the main axle 5 in. diameter. Spring spokes were applied to the driving wheels, which were about 6 ft. diameter, and the front of the engine was mounted upon helical springs.
There were three travelling speeds provided, the ratios of the steel gearing being 6 to 1, 12 to 1, and 22 to 1. Sufficient water was carried in the tanks for a 20 mile run. The weight of the engine was under 10 tons. A large cab covered the crankshaft, eccentrics, and main bearings; the speed clutch levers were inter-locking, so that it was impossible for a careless engine driver to put two speeds into gear at once. Sectors were fitted to the front axle outside the leading wheels, and the steerage chains were adjusted to prevent back-lash, the steerage action was quicker than usual, a very necessary point for fast travelling; the front wheels had chilled bushes running on case-hardened axle ends. The working parts on the top of the boiler, not covered by the cab, were neatly boxed in to prevent them being covered with dust."
An eye-witness supplied the following account of a run made with the engine previous to its shipment for India. "I wish you had been with us on Monday when the inspector came. We had a grand run; started from the opposite end of Leeds, three miles from the works, about half-past three p.m., and ran over our country roads, where the track was just about the width of the engine, and we had some steep hills — plenty of them one in ten — to go up and down, but no long inclines, some of them were so steep we were obliged to put the slowest gear in to get up. However, the inspector was well pleased with the way the work was done. Just at the finish of the eight miles stretch we had to go down into the valley of the Wharfe, and it is no exaggeration to say that for a short distance the declivity was one in seven, and though we got down very well I could not help wondering what the result would have been if the brake strap had broken. We then had a mile of splendid road, but could not get along at any pace in consequence of hills and traffic; but after leaving the village of Harewood we had four miles of straight road wide enough, but with some long rises of one in twenty. We passed the first milestone in five minutes; the second in seven minutes — having to let a trap pass; the third in six minutes — eased to let carts pass; the fourth in less than five minutes. Running the four miles in twenty-three minutes. The inspector was abundantly satisfied. Three tons was hauled behind the engine, and the tank full of water lasted for the sixteen miles, and would have supplied the engine for four more miles."
The omnibus sent to India with the above engine is shown by Fig. 102. We now have pleasure in referring to the three beautiful high-speed road locomotive engines, of excellent proportions, constructed by Messrs. McLaren for the 'Fourgon poste' service in the south of France. One of these engines is shown clearly by Fig. 103.
The Engineer for 16th December, 1887, says: — "This service is in the hands of different contractors, and altogether apart from the postal service of the State. It consists of the collection and delivery of parcels and light merchandise in districts remote from railways or indifferently served by them. Strange as it may appear, many of the largest railway centres are also centres of the 'Fourgon poste' services, which collect their parcels in one town and convey them by horse conveyance, and deliver them in another town many miles away, although there may be a direct line of railway between the two places. The excessive charges of the railways for goods carried grand e viiesse, and the excessive time occupied in the conveyance and delivery of goods carried at petite vitesse rates, enables these contractors or carting agents to do a large business, many of them requiring several hundred horses for their work."
Some four years ago Messrs. McLaren made one of their compound road locomotives, and tried it for this parcel service with so much success that in a short time others were ordered.
The engines are of the compound type of 12-horse power nominal, constructed for a working pressure of 175 lbs. per square inch. The engine shown in Fig. 103 is one of the three which are running regularly between Lyons and Grenoble, which are about 70 miles apart. "The goods are collected and packed in the wagon — which will carry about six tons — during the day," and one engine starts out of each town in the evening and delivers its load at the other end the next morning. One engine is kept in the shed in reserve so that the engines can be washed out properly and kept in good running order. The road for about forty miles is very hilly, some of the gradients being 1 in 11. There are also some long hills, one of about four miles with an average rise of 1 in 40. "In one part it descends a zigzag course down to the bottom of a very steep valley." Part of the road for several miles runs along the shelving side of mountains, the rocks rising precipitately on one side and the ground falling away on the other side, there is no protection whatever on the lower side, and a moment's forgetfulness on the part of the steersman might plunge the whole train down a precipice 500 feet deep. As the whole journey has to be made in the night "it is of the greatest consequence that the engines should be fitted with ample brake-power and an efficient system of lighting. They are therefore fitted with a steam break — worked by McLaren's patent steam reducing valve — as well as the ordinary hand brake. The former can be applied instantly with such force as to pull the engine up with full steam on, and at the same time, by means of a chain, the brake is albo applied to the wheels of the wagon. The engines are fitted with an arrangement for burning ordinary gas. This is compressed into a receiver up to a high pressure, and reduced down to burning pressure by means of a patent regulator or diminishing valve, which Messrs. McLaren specially designed for the purpose. One charging of gas is sufficient to give a brilliant head-light and supply the signal lights for the round trip of 140 miles."
The engines are very economical in coal, burning from 5 to 8 cwt. in the trip depending on the condition of the road. The spring arrangement may be described as absolutely perfect, for though the engines have run many thousands of miles there has never been a single breakage in connection with the springs. The roads are not good even where level, as they are full of great holes, and many open drains run across them without any covering. Hugh stones as large as a man's head are constantly rolling down from the mountains and lodging on the road, so that when the engine comes along at such a speed it has either to drive them out of the way or ride over them, which tries the springs, and is a severe test for shewing the stuff they are made of.
A large signal whistle is fixed to each engine. The steersman's seat is mounted upon a spiral spring. The engine work is neatly cased in as shown, and part of the details are under the cab. Most of the gearing is placed between the wrought iron side plates carrying the crankshaft brackets. The safety valves are spring loaded, the central spring being in compression, out of sight so that it cannot be tampered with. The engines run eight miles an hour for hours together, but of course run slower up hill. Each engine weighs 15 tons fully loaded. The average mileage of each engine is about 15,000 miles per annum. The number on the name-plate of one of these three engines is 288, which shows good work for the time Messrs. McLaren have devoted their energies to road locomotive building. These are splendid examples of high speed compound road locomotives.
And we are pleased that this work contains the description of such a favourable example as the one we have illustrated by Fig. 103; shewing as it does that during the last 23 years considerable progress has really been made in this industry.
The wheel illustrated in Fig. 104 has been recently brought out by Messrs. J. and H. McLaren, and Mr. I. W. Boulton. It is being manufactured by Messrs. John Fowler and Co., Messrs. Aveling and Porter, and Messrs. J. and H. McLaren.
"Referring to the illustration it will be seen that the flange of the wheel is very deep. Square holes are cast in the face, into which are fitted blocks of wood 6.5 in. by 9 in., bound with iron, which slide loosely in and out of the holes, just like a piston. These blocks are bedded on india-rubber or felt, to deaden the vibration, and are kept in position by bolts with lock-nuts, which pass through the wheel flange, as shown in the engraving. The blocks are further retained by a stiff spring on each side of the bolts, which has about f in. compression. The blocks are set in two rows on the wheel rim, one row half a space in front of the other. The action is as follows: — The blocks in their normal position project a little from the rim, but when the wheel turns, the blocks, coming to the ground, of course yield and present a flat surface to the road. As the wheel continues its revolution, the blocks, rising from the ground, are brought back to their normal positions by the action of the stiff springs, and so the action continues.
It will be seen that the grip of the wood blocks is very great, and no slipping can occur. The fact of the blocks being of wood prevents any damage being done to the road, and the combined action of these blocks and the india-rubber renders the wheels comparatively noiseless.
The wheels now in use, we are informed, have given great satisfaction to their respective owners, the cost of keeping them in repair being much less than ordinary wheels, where the crossbars have to be replaced every few months."
On paved streets the use of these wheels is specially advantageous, for not only is the tractive power of the engine enormously increased, but any possible damage to the paving setts, caused by the chipping action of ordinary wheels, is entirely avoided. A considerable number of engines furnished with these wheels have been at work in the Manchester district for some years, and the results have been so satisfactory that certain local authorities, who, by virtue of special powers had practically prohibited the use of traction engines within their districts, have waived their restrictions in favour of engines mounted upon these wheels.
Experience has shown, that an enormous amount of wear and tear is occasioned by the shocks sustained by the engines in travelling over rough and uneven roads without springs. The wood-block wheels just described serve as an excellent spring, effectually breaking the shocks, and increasing the durability of the engine.
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