Content copyright © Tramway Museum Society of Victoria Inc.  Reproduced with permission.

Home RUNNING JOURNAL Reflections Cover Photo : Mal Rowe

One of the smaller classes of Melbourne tram was the W3. With only sixteen examples being constructed, four complete vehicles still exist retained by tramway museums. With the return to traffic of the TMSV’s W3 667 shortly, it would be interesting to return to their beginnings nearly 70 years ago by reading the following contemporary article.

The last tramcars built by the Melbourne & Metropolitan Tramway board have been designed with the special objects of improving the riding qualities and reducing noise. These expected improvements have been more than realised. These cars, which are known as the W3 class, have been built on the same general outline as the standard car known as the W2 class. They have been designed and built under the supervision of the Board’s Chief Engineer Mr T P Strickland by the staff at the tramway workshops at Preston.

Each of the new cars are 47 ft long, 7ft 6in wide over pillars and 9ft wide over footboards. They are 10ft 5in high from rail to roof and weigh 15tons 14cwt. The seating capacity is 52 persons but the total crush loading capacity is 150 passengers. There are three entrances on each side to the smoking compartment, which has cross-bench seats to accommodate 16 persons. These entrances are not fitted with doors but have canvas weather blinds fitted to spring rollers for use in wet weather. Saloons open off either end of the vestibule and are provided with sliding doors. The windows which drop their full depth, have louvre blinds fitted and the seats are made of three-ply moulded forms. The bodywork of these cars have been built of steel, electrically welded, the woodwork being used only on the interior facings on the steelwork. Considerable strength combined with lightness has been achieved with this design about 2.5 tons in weight having been saved over the wooden superstructure on a steel underframe for same design of car. The sills are of 3 ½ in x 2 ½ in x 5/16 in angle steel, the belt rail is 2in x 2in x 5/16 in angle and the cant rail is 3in x 2 in x ¼ in angle. The pillars are of 1 ½ in x 1 ½ in x 3/16 in tee section and the roof ribs are of 1 ¼ in x 1 ¼ in x 3/16 tee section. The bolsters are of the box type built up with 10 in x 7/16 in top and bottom plates and 8 in x ¼ in web plates strengthened with ribs, the whole electrically welded together. The cross members are 4 in x 2 in x 7.09 lb channel section and the end sills 7 in x 2 1/8 in x 9.75 lb channel. Panels are 14 gauge and the letter board 16-gauge steel, all electrically welded to the pillars.

The roof is of 5/16 in plywood covered with Caledonian roofing, the roof sticks are of Australian Blackwood and the interior finish of the plywood roofing is Australian walnut. Tongue and grooved Baltic pin ¾ in thick forms the flooring in the saloons and wood slats in the smoking compartment. Aluminium angle finishing pieces are fitted to all doorways and along the footboards, both reduce wear and to show up the edges at night. Polished plate glass 3/16 in. thick is used for the end windscreens, while the remainder of the car 26oz mechanically-drawn glass is used. The sashes and louvred blinds are made to run in extruded brass sections, screwed to the pillars to form the sash guides.

The bulkhead framing and doors are made of Tasmanian mountain ash, panelled with Queensland maple. The cross bench seats in the smoking vestibule, and the saloon seats are built of Tasmanian mountain ash and blackwood framing around three-ply moulded forms. The outside of the car has been finished in green and cream enamel. In order to allow the use of 33-inch diameter wheels in the trucks, the step heights have been graduated. The height from rail to footboard is 15 ¾ in. and from vestibule to saloon 9in.

An entirely new design of bogie truck has been developed in connection with this car. This truck is new to tramcar design in that the springing has been made similar to motor car practice, ie long semi-elliptic springs clamped to the axle boxes and attached to the truck frame or chassis by shackles, through which the drive is taken. This arrangement eliminates the use of horn guides and thereby cuts out considerable noise. The maximum size wheels used in tramcar operation (33-inch diameter) have been used. Large wheels give a smoother rolling action along the rails than smaller ones, which reduces the impact at crossings and special work and the noise of the rolling action on the rails. The large wheels also have fewer tendencies to corrugate the rails. Each truck is fitted with two 4hp motors giving equal traction in each wheel. The swing links for the bolster have been made 12 ½ in. long as compared with 10 ½ in. on smaller wheel trucks, thereby giving a better riding condition for the car body.

The materials used in the construction have been selected to give minimum of weight fro the strength required. All castings where strength and wearing are required have been made of steel, and others such as axle box lids of aluminium. All springs have been made of spring alloy steel. Electric welding has been availed of where possible in the construction of the trucks. The bolster is built up in box sections with top and bottom plates ½ in. thick and web plates ¼ in. thick and electrically welded with no 10/8 run along all four edges.

The side frames for the first of these trucks were made of cast steel, but these proved to be rather heavy and the mild steel side frames were developed. These are made by using a pieces of 7 in. x 3 ½ in. x 15 lb I-beam. The process of manufacture in these frames is interesting and is briefly described. First a section is cut away from the web by oxy-acetylene flame. The top and bottom flanges are then bent to the correct shape, the web being cut away allowing the angle smith to carry out the work much more easily than bending the full 7 in. depth section. The difference of length between the top and bottom flanges after bending is about 2 in. which represents the amount of draw that would have had to take place had the web not been cut away. After forging to shape the web is again joined together by electric welding and the whole section is thus made solid once more. It is only the use of electric welding that has made this job practicable. Side frames thus made have proved cheaper than the steel casting and have the advantage of being lighter and more ductile and homogenous.

The braking on these trucks is also a departure from the conventional design of fitting one brake cylinder on the car body and operating through foundation brake rigging to the brake gear on the trucks. On the new design, the brake cylinders have been fitted upon the trucks and operated directly upon the brake beams. Clasp brakes have been fitted to the wheels and although this is standard practice in railway rolling stock, it is new to tramcar design. The advantages found with the clasp brake compared to single shoe brake are smoother retardation, less tendency to skid the wheels and only half the consumption of the brake shoes per annum for the same class of car. The air cylinders are connected to the straight air brake system through a relay valve by a flexible hose. The hand brakes operate for one truck only and are not interconnected throughout the car. The use of the two brake cylinders on each truck eliminates heavy brake cylinder on the car body and all brake levers, rods, pins, etc., with their loss of efficiency weight and noise.

The car is equipped with four 40 hp Metropolitan-Vickers motors made in Australia. The gear ratio is 13/77 and the free running speed is 20 mph. The schedule speed works out at 11 mph with eight stops of 5 second each per mile. The power controllers are of the General Electric K35JJ series-parallel type and are also made in Australia. The line breakers are English Electric type No. 6 form C, the compressor is the Westinghouse DH 16 and the motorman’s valves are Consolidated Brake type C. The hand brake, trolley bases and destination signs are of the Board’s own design.

Complied and reprinted from “The Electrical Engineer and Merchandiser” for March 1932 by Graham Jordan.

When the “W3” Trams Were New Graham Jordan - Running Journal Jan 2000