The question of the design of small locomotives for use on pioneer lines has been always a difficult matter.
The needs of the railway contractor have called for such locomotives, for which several systems of power have been tried. In many ways the electric locomotive has distinct advantages over its rivals, steam and compressed air, for these narrow gage lines. Reviewing these advantages briefly, we see that the electrical equipment is more economical to work, as one good stationary engine develops power much more cheaply than several small locomotives. Again, the electric locomotive can be more readily designed for narrow gages than steam or compressed air locomotives.
A new system of equipment of such lines is now being introduced into this country by Mr. Arthur Koppel, of 96 Leadenhall Street, E. C. The keynote of this system is flexibility, the arrangements being such that extensions or alterations can be readily effected. In fact, the line is portable, and it is claimed also to be cheaper than the ordinary construction. The overhead conductor is employed, as can be seen from Fig. 1, which gives a general view of a locomotive and train of skips on a line actually at work abroad. The supports for the wire are not provided by separate posts and brackets in the usual way, but by arched carriers attached to the sections of railway line, thereby forming a portable section of the electric railway, as illustrated by Fig. 2. The steel carrier or "arch" is fixed to one of the sleepers, which is made of sufficient length for that purpose. On the straight line these line supports are placed about 25 yards apart. In curves of a small radius each section of tramway is provided with an arch, to keep the line of the wire as nearly as possible parallel to the curve of the line. Apart from these special extended sleepers with wire carriers attached, the line is constructed in the ordinary mariner with rails 14 lb. per yard and upward.
As the electric locomotives are lighter than steam locomotives, the weight of rail required is somewhat less. The special trolley for erecting the wires along the railway line is shown in Fig. 3. This consists of an ordinary four wheeled platform wagon with ladder, and wire drum with tightening gear and clamps or grips for anchoring the trolley to the line. The wire is led over a sheave on top of the ladder and fixed to the picket post at the beginning of the line. When erecting the wire the trolley is pushed beyond the first carrier arch, clamped on to the rails, and the wire is then tightened by means of the tightening gear. It is then firmly fixed to the insulator on the carrier arch The tension in the copper wire is taken up by a second portable ladder, which is also provided with a tightening gear and can be clamped to the rails in the same manner as the trolley, so that the trolley can then be pushed behind the second carrier arch and the process previously described repeated. By the tension in the wire the carrier arches acquire the necessary stability, while without the procedure previously described it would be impossible to use such light arches attached to the sleepers. On permanent lines, the extreme ends of the wire are attached to properly anchored picket posts.
On portable lines, on the other hand, the trolley with the wire drum is fixed to the rails at the end of the line, as shown in Fig. 3, so as to enable the line to be lengthened or shortened, as may be required, with ease.
Care is taken in insulating the drum and ladders so as to prevent leakage from this erecting trolley to earth. The feeders from the power house to the overhead wire and to the rails respectively are erected on light iron posts, which have also been standardized by Mr. Koppel. A specimen of these posts with an anchored stay is shown in Fig. 4. All these details are arranged for convenience of the contractor required to rapidly equip a line of railway, which can also be removed as soon as the work has been done.
Fig. 4. - LIGHT POLE FOR CARRYING THE FEEDERS.
Fig. 5. - THE KOPPEL LOCOMOTIVE.
The locomotive used is varied in form with the gage of the line, but we are particularly concerned with those for gages under 24 inches. One form of such locomotive without a hood to protect the driver is shown in Fig. 5. In this locomotive the gear is the same as that of the next illustration, but it is securely boxed in a watertight iron cover. The controlling gear is then placed vertically in front. Figs. 6 and 7 show the details of the electrical and mechanical parts of this locomotive when fitted with a platform at either end, and with a hood. The motor. M, is of the internal pole type, and is supported on the underframe of the wagon. A double gear is used. The first is a spur gearing, connecting the motor to a countershaft placed under the motor. This gear reduces the speed of rotation to about 200 revolutions. The countershaft is then connected to the two axles of the trolley by chain gearing. This gives the necessary flexibility between the car body and the wheel required, as the springs give to any inequality of the rails. In this gearing there is no change of speed. The underframe is provided with spring axle boxes, and also with spring buffers and drawbars.
The speed of the motor can be regulated within very wide limits by the regulator, R. An effective hand brake is also provided.
For gages of 20 inches and upward the motors can be mounted on springs and attached to the running axles inside of the wagon underframe. This construction is particularly recommended by Mr. Koppel where, in order to mount heavy gradients, the dead load of the motor car must be assisted by the paying load to produce the necessary adhesion. In such cases several motor wagons would be used in the same train. As regards the working voltage, this can be varied to suit special requirements, but the locomotive we illustrate was designed for 110 volts. At this pressure its possible working speed was at least eight miles per hour. The supply of power is also a matter not referred to particularly, as in many cases a lighting plant is used by the contractors, which could also be employed to provide the necessary energy for the electric railway. The good work done by small electric locomotives in the excavation work for the Waterloo and City Railway will convince our large contractors of the valuable service which electricity can render both above and below ground. - The Electrical Engineer.
 Electrical Engineer, vol. xvi., p. 499.
A connection between Servian and Roumanian railways is to be established by bridging the Danube. It is reported proposals have already been made to the governments interested, by the Union Bridge Company, also by British and French constructors. - Uhland's Wochenschrift.