AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

REVOLUTIONARY DESIGN IN NE LONDON TRANSPORT COACHES

12th May 1939, Page 38
12th May 1939
Page 38
Page 39
Page 40
Page 38, 12th May 1939 — REVOLUTIONARY DESIGN IN NE LONDON TRANSPORT COACHES
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

Under-floor Engines, Unit Chassis and Body Construction, Air-operated Pre-selective Gears. Chassis by Leyland, Bodies of Park Royal and L.P. T. B. Manufacture

Respectively Two New Types for Private Hire and Green Line Services. Safety and Comfort for Passengers and Drivers Manifest as Considerations of First Importance in Layout and Equipment

TWO new types of coach are being introduced, by the London Passenger Transport Board. They are for use as Green Line service coaches and for private-hire work respectively. Altogether there will be 87 new vehicles, 75 being for the former purpose and 12 for the latter.

In both cases the basis is a flat-engined chassis built by Leyland Motors, Ltd., whilst the bodies of the Green Line machines will be constructed in the Board's Chiswick works and those of the private-hire coaches will be products of Park Royal Coachworks, Ltd. Although of novel design in respect of general layout, the machines incorporate well-tried components.

Not the least interesting feature is that unit construction of body and chassis is employed. To the straight frame longitudinals, outrigger members are attached in such a manner that the body pillars may be mounted directly on the chassis without the use of bottom framing. The outriggers and body pillars are in line with the cross-members, with the result that a high degree of rigidity is afforded, body whip is minimized.

84 there is freedom from body noises and long life is assured. As there are no frame arches, the floor, which is at a moderately high level, is quite uninterrupted, and passes above the power unit which is disposed amidships with the axis of the crankshaft on a longitudinal centre line. This affords maximum body space together with excellent weight distribution. Moreover, the transmission line is straight and central.

Accessibility is good, because the cylinder head lies close to the off-side body panels. There are also trap doors in the floor giving access to other parts and to the transmission units

Suitably modified for the conditions created by this new arrangement, the engine is a standard Leyland 8.8-litre six-cylindered compression-ignition unit. It is mounted flexibly, having limited freedom of movement. Provision is made for easily reaching the filters, injectors, injection pump, tappets, etc. One important advantage of the central engine is that the radiator may be at the front.

Power is carried forwards by an extension of the crankshaft, from which drives are taken to the fans for the radiator and the heating and ventilating system respectively, to the dynamo and to the air compressor_

At the other end of the unit are an hydraulic clutch and pre-selective gearbox. In this connection it is of note that compressed air is employed not only for the brakes, but also to actuate the gear-engaging mechanism. In consequence the pedal pressures for the brake and gear controls are no heavier than in the case of a small car.

Furthermore, in the improbable event of a pressure failure, which obviously would reduce the efficacy of the brakes, no gear can be engaged, which fact constitutes a valuable safety feature.

Another point of note is that where a driver is so far removed from the engine that it is by no means distinctly audible to him, a transmission system calling for little skill or judgment in the changing of the gears is virtually an essential.

The air system provides for a big reserve of power and the brakes themselves embody automatic adjusters. B5 Considering now the Green Line vehicles, we find that the body components in the main conform to orthodox L.P.T.B. design. This also applies largely to the external treatment and the interior finish. A noteworthy point, however, is that care has been taken to eliminate dust traps and to facilitate cleaning.

All seats face forwards, and afford accommodation in every case for two persons. Tubular seat framing is used and Dunlopillo fillings give good comfort. Access to the shloon is gained by a front sliding door, arranged outside the body panelling. At the rear of the central gangway is an emergency door and at the front is a door to the cab.

Excellent driving visibility especially to the near side —invaluable under foggy conditions—is afforded by the avoidance of a full-width front. On the near side of the cab, in front of the bulkhead, is a short sloping dummy bonnet. Thus, the driver can see the road just in front of the near-side front wheel. Moreover, the near-side cab window can be fully opened.

On all matters affecting driving comfort, care has been lavished.

Excellent Saloon Outlook.

In the case of the private hire coaches, these have Park Royal metal-framed body construction, and similar front-end treatment and heating arrangements. In the upper parts of the vehicles, however, there are marked differences. Of the observation type, the saloons provide an outlook that is comparable with that of a coach with a full-dropping head.

Widely spaced apart, the slender pillars, support a high cant rail, right up to which the side windows extend, Above the rail are curved lights moulded in Triplex toughened glass. In the centre is a folding roof operated by a handle at the front. This gives a clear opening to a point above the rearmost seats. Even when closed, the coach is exceptionally light and is characterized by an airy and commodious atmosphere.

Blinds are fitted to all the curved lights for use in strong sunshine. A wireless set is built-in to the front bulkhead, its aerial forming a " motif " over the front.

In accordance with standard London Transport coach practice, the floor is fiat, having small wheel arches, and there is a carpet along the central gangway. Like the service vehicles a forward outside-sliding side door is provided, but the emergency door is on the off side behind the rear wheel.

As before, all seats face forwards, but the rearmost seat is for five persons. The total capacity is 33.

An interesting constructional feature is that additional rigidity is afforded by the employment of two pairs of interior vertical supports, which run directly from the chassis frame to the top roof rails.

Precautions Against Noise.

To enhance the comfort of passengers, special provision is made to silence the engine air intake, whilst insulating materials are employed to prevent noise and beat from Penetrating into the saloon. All mechanical and electrical parts have been designed and accommodated with a view to accessibility.

Both these new types represent definite progress in high-class passenger-vehicle design. They are a combined effort, being the outcome of a long period of collaboration between the bus and coach department of the Board and Leyland Motors, Ltd. From the point of view of cost of operation, it is confidently thought that the small additional initial expenditure involved will be more than compensated by the easier and reduced maintenance necessary and by the longer life prior to obsolescence.

With regard to appearance, the coaches are unquestionably handsome, tasteful and dignified, whilst the complete lack of indication as to the location of the power unit is definitely intriguing.

Tags

Locations: LONDON

comments powered by Disqus