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Rebodied EMUs take over South African commuter routes

01 Apr 2002

INTRO: Unable to afford new trainsets, South African Rail Commuter Corp is fitting new bodies to old EMU underframes. Rollo Dickson has the story

STRIKINGLY refurbished rolling stock is appearing in Johannesburg and Cape Town, where the electric multiple-units that work South Africa Rail Commuter Corp's suburban services are typically 30 years old.

Designed in the mid-1950s, more than 300 steel-bodied motor and trailer cars designated 5M were imported from Metropolitan Cammell Carriage & Wagon Co in Birmingham in the UK. This design was modified to produce the 5M2A, and more than 4300 cars of this type have moved the bulk of South Africa's commuters since they were introduced in 1961. The last entered service in 1985, augmented only by eight Type 8M 12-car sets a few years later.

The 5M2A sets had GEC electrical components and were built by Union Carriage & Wagon of Nigel, near Johannesburg.

During the 1990s designs were prepared for the 9M, a modern commuter train to be imported from Japan, but funding problems put an end to this project.

Pilot refurbishment

Two completely rebuilt 5M2A sets were placed in service in 1998 and 1999 (RG 4.98 p214). Largely for security reasons and to take account of rising vandalism, they featured substantially different seating, windows and door fittings. Designated 10M and 10M1, they were distinguished by a single, centrally-placed windscreen and driver's position. Two further rehabilitated sets with minor refinements were classed 10M2 and proved very successful.

Owing to the increasingly prohibitive cost of acquiring new rolling stock, SARCC, which reports directly to the Department of Transport, placed orders for the supply during 2001-03 of new bodywork for 44 motor coaches and 132 trailers, using extensively overhauled underframes and bogies from 5M2A stock.

The project was divided in half, 22 motor coaches and 66 trailers being awarded jointly to Siemens and Union Carriage, the rest to Bombardier in association with Transwerk, a Transnet subsidiary. The 88 Siemens-Union Carriage cars will form Class 10M4, and will have bodyshells from Corten steel. The first set entered service recently in Johannesburg.

Two types of bodyshell

The other sets, to be known as Class 10M3, are to have stainless steel bodies for use in Cape Town. Interior fittings will be similar in both series, except that, because of the cold highveld winters, the 10M4 will have heaters. These are attached to the bodysides below seat level, leaving the floor clear for cleaning. The two contracts total about R400m.

Although of corrosion-resistant Corten steel, the 5M2A bodies did not last well near the coast, and stainless steel was specified for the 8M sets. The new 10M3 bodyshell is based on that used in the 8M. It is essentially a Hitachi design derived from experience built up by the Budd Co, now part of Bombardier Transportation. A detailed structural stress analysis ensures compliance with UIC566 specifications in terms of passenger loads, end tensile and compressive forces, fatigue analysis, natural frequencies and buckling analysis under static and dynamic conditions. Manufacture of the bodyshell panels is being undertaken by RSD, Boksburg, Gauteng, who supplied the Class 8M shells.

The Budd concept uses simple and effective plain spot welding, visible from the outside of the coach, to attach the skin to the side framing. This complies with UIC566 OR and with Hitachi standards.

In the course of refurbishing, the entire bodyshell is discarded. Underframes are exhaustively checked for cracks, strength and dimensional correctness. New cold-rolled solebars are welded on in place of the old, and the brake gear is overhauled. Brackets are fitted where needed to attach electrical and other components. To facilitate replacement in the event of damage, the new superstructure is huckbolted to the underframe.

The driver's cab is a separate module in all-welded Corten steel and can be detached for repair in the event of collision damage. A glass fibre composite nose has an integral windscreen, plus head, tail and marker lights. Provision is made for housing rear-view mirrors beside the cab that are easily visible from the central driving position.

Controls generally duplicate those that are standard in the 5M2A sets. Behind the driver's cab, a full-width equipment compartment houses the microprocessor-controlled chopper control unit, a new direct-on-line static auxiliary converter, and a high speed circuit breaker. Regenerative and rheostatic braking are provided.

Vandal-resistant interiors

Saloon interior surfaces susceptible to deliberate damage were minimised. The longitudinal side-mounted cantilevered seats are vacuum-formed with thermoplastic bases and backs attached to steel frames. Individual seats are provided for each passenger, replacing the full-length benches characteristic of the 5M2A.

Interior panels are of vacuum-formed, fire-retardant polyethylene, attached to the bodyshell by brackets positioned to ensure minimal jointing. The panelling is slotted into coated aluminium mouldings, screwed to the bodywork, leaving no fixing visible from inside the coach. Side panels are neatly dished over window frames, eliminating the need for extra interface parts.

Ceiling panels of the same material, similarly mounted, curved to follow the coach profile and ribbed for stiffness, slot into a moulding that forms part of the centrally located fluorescent light fitting, which is continuous along the car. The housing is an aluminium extrusion and all parts clip into it. The light diffuser is of impact-resistant polycarbonate. A full-length aluminium panel housing ventilation outlet grilles is mounted immediately next to the lights, together with grilles concealing public address speakers. Grab poles and handrails are formed of stainless steel tubing.

At each doorway, a half-height, rigidised stainless steel draught screen is provided beside the nearest seat. Structural provision is made for fitting end doors, a feature of the 10M prototype and of the original 5M2A.

To avoid recurrent difficulties experienced with 5M2A doors, those on the refurbished sets are fitted outside the car, sliding on concealed bottom guides in the threshold, which is angled to prevent anyone clinging to the exterior. There are two pairs of bi-parting doors in each motor coach and four pairs in each trailer. Doors are released by the guard, then opened manually by passengers. The Faiveley door mechanism, enclosed within a full-length pelmet, is accessed for maintenance through a locking section that hinges upwards.

Ventilation uses brushless DC motor-driven fans mounted in the roof cavity which draw in air from above. They maintain a cool environment at head height for standing passengers, while standard 'monsoon' ventilators exhaust stale or hot air. Half-drop windows are clamp-fitted, without rivets. The panes, of unbreakable polycarbonate, can be removed from outside without disturbing the frame.

Provision is made for fitting television 'infotainment' equipment by outside contractors. Housing in a cubicle in the leading motor coach is provided for removable transmission and control units, while monitors are to be mounted in secure steel boxes in the ceiling cove of each car.

The current projects initiate a rolling plan which will see the entire 5M2A fleet rehabilitated, possibly with 200 to 400 cars treated each year, although this depends upon financing.

TABLE: Table I. Principal data of rebuilt SARCC EMUs

Motor car Trailer car

Gauge mm 1067

Length over couplers mm 19410 19396

Height mm 3965

Width mm 2845

Distance between bogie centres mm 12497 13564

Bogie wheelbase mm 2743 2134

Wheel diameter mm 1054 864

Passengers seated 43 52

Traction motors 4

Power supply 3 kV DC

Continuous rating kW 880

Starting tractive effort kN 150

Maximum speed km/h 100

Tare mass (10M3) tonnes 63 32

CAPTION: A Type 10M4 motor coach with new Corten steel body for use in the Johannesburg area

CAPTION: For many years South African commuters have travelled in these Type 5M2A units, seen on the Simon's Town line south of Cape Town (above)

To resist corrosion in the coastal atmosphere, the Type 10M3 trainsets for Cape Town (right) will be fitted with stainless steel bodies