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6th January 1967, Page 46
6th January 1967
Page 46
Page 47
Page 48
Page 50
Page 46, 6th January 1967 — LONDON TRANSPOR DEVELOPMENTS
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Which of the following most accurately describes the problem?

quieter Routemasters an one-man double-deckers

WHAT is a noisy vehicle? This is a very good question because so much depends on the individual and on the type of noise. Pitch and rhythm are factors to take into account, quite apart from the actual volume of noise. And a noisy bus in a closed-in street might appear to be a quiet vehicle out on the open road.

Noise in relation to vehicles is a very topical subject right now for regulations governing the maximum amount of noise which can be emitted by road vehicles are expected soon. Just how soon is, at the moment, anyone's guess, but draft regulations published by Mr. Marples in June 1963 were intended as a guide so that vehicle manufacturers could plan for the introduction of quieter vehicles "by the beginning of 1968".

The regulations then recommended 88 decibels (dB) as the maximum limit for existing vehicles and 86dB as the maximum for heavy commercial vehicles and buses introduced on and after January 1 1968. New vehicles on test, however, would have to meet slightly lower requirements, owing to the different conditions pertaining at the roadside measuring sites. A bus, for example, would have to meet a maximum noise level of 85dB at full throttle for existing vehicles and 83dB for all new vehicles registered from January 1968.

Since the original proposals were made there have been modifications and some time ago it was thought that the regulations would be 87dB maximum for existing heavy vehicles and 85dB for all new vehicles. After tests by the Road Haulage Association and the Traders' Road Transport Association it is now believed the maximum will be relaxed to 89dB or even higher for new vehicles. On the other hand the Noise Abatement Society is pressing the Ministry for a maximum as low as 80dB for all vehicles, including those already in service.

Whatever the outcome, London Transport was quick off the mark and early in 1964 started a series of tests with Routem aster buses to see how these vehicles would match the proposals at that time. Inspired by Mr. K. Shave, chief mechanical engineer (bust and coaches), the Board has remained very noise conscious sinc then.

I have never considered the London Routemaster to be a nois bus—personally I think two-stroke motor-cycles and bubble cai are much more offensive. However, it is true that the Leylanc engined version of the Routemaster, of which there are 585 examplt out of the total Routemaster strength of about 2,600, are generally little noisier than the AEC-engined counterpart. Some of these a] reported to have exceeded 90dB on occasion. This is probably th to induction roar, caused by the omission of an air cleaner from ti engine—standard London Transport policy—but even these bus( are not really offensive in my opinion. To a "tuned" ear, thc produce a different sound, but I would not have considered the particularly noisy. The AEC engine is possibly designed to alio for the lack of an air cleaner, due to its widespread use with LTB.

The AEC-engined Routemasters tested in standard form can out about two decibels below the noise level of the Leyland versio so it is not surprising that a Leyland-engined bus was chosen f4 experimental sound deadening. Ricardo and Co. Engineers (192 Ltd. carried out the modification, which was to RM1719, ar consisted basically of the screening of the engine almost complete with sound-deadening panels. This resulted in an improvement 811c1B maximum on this bus.

Experiments continued LTB then produced its own sound-deadening kits and fitted thei to 24 AEC-engined Routemasters numbered in the lower 70( as they passed through Aldenham works for routine overhat Some of these buses now produce maximum readings below 80dI As an additional experiment RM738 was fitted with a modifit radiator grille in which baffles replaced the normal mesh. It w; reported that this grille, quite apart from being less attractive the be normal, had a bad effect on engine cooling. Furthermore, the mprovernent in noise reduction was less than 1 dB. Consequently was rather surprised to encounter the vehicle in regular passenger wrvice one hot day last July. The bus was operating from Edmonton ;arage and I seized the opportunity to try it out there and then.

As already suggested, the effect of noise is a very subjective natter, but I was exceedingly impressed with the performance of Z.M738. Sitting in the front lower saloon seat, immediately behind he engine, the most prominent sound was the gearbox, which was, f anything, one of the quieter units of its kind fitted in London loutemasters. However, the main point of the experiment was to -educe external noise—Routemasters, with both AEC and Leyland :.ngines, are already reasonably quiet vehicles to ride in. So I 'lipped off the bus at a set of traffic lights, where there was a queue )f. cars waiting in front of the bus. As the traffic moved off, any noise from RM738 was drowned by the noise from the private cars.

Still going quietly In Tottenham recently, I came across RM738 again, still with its special grille, about to pull away from a bus stop and with no other traffic close to it. This time I was able to hear the engine, but only just. It was a very muffled (and quite pleasant) sound dominated ny the low whine from the epicyclic gearbox. Incidentally, on both )ccasions there was no apparent evidence of engine overheating, ilthough I understand that this bus does run slightly warmer than Routemaster with standard grille.

Another Leyland-engined Routemaster selected for noiseleadening was RM1980. Indeed this conversion was carried out nefore the AECs. In this case an air-cleaner was fitted as part of the ;xperiment, and the maximum noise (nearside) was reduced from 39dB (untreated bus) to 82i-dB with complete treatment. A ride on his bus in service recently showed little improvement inside the ower saloon, compared with a standard Leyland-engined Route

master, although it was noticeable how the engine (already acceptably quiet) grew quieter as the bus filled-up.

I made several attempts to hear the bus pull away from the outside, but in each case I was thwarted by the presence of other traffic. One final attempt at the foot of Highgate Hill to hear the bus failed completely when a heavy lorry roared past just as the bus moved off. Nevertheless the inability to hear the bus above the noise of other traffic was surely a testimony to the success of these useful experiments.


Recently I had the chance to kill two birds with one stone— namely sample a London Transport Dainller Fleetline experimentally fitted with a Cummins V6 diesel engine and, at the same time, watch the effects of operating this vehicle as a one-man bus with the top-deck sealed off. The bus in question was XF3 and the run was made over the 424 route from Reigate to East Grinstead.

From an operating point of view, it was interesting to compare this run with one I described in COMMERCIAL MOTOR on March 11 1965, when the Fleetlines were being operated with a conductor and the top-deck open all day. The journey I made this time was on the same scheduled run from Reigate, leaving there at 11.21 a.m.

Dealing first with the performance of the vehicle: I travelled at the rear of the lower saloon to get the full effect of the engine. Standing at stops, the unusual "rattle" of the V engine was most noticeable, though this is not to say that the engine was noisy. It was simply an unusual sound, accompanied by a slight shuddering, though no worse than that encountered on many of LTB's other rear-engined buses with in-line engines. This problem of Cummins engine shudder at idling speed has, I understand, since been solved by Daimler Transport Vehicles Ltd.

The moment the bus moved off, the smoothness of the Cummins engine under power was noticeable and it appeared to be quieter and smoother than a standard Gardner-engined Fleetline. I say "appeared" quite deliberately because again, this is a subjective thing. In actual fact I believe the Cummins-engined bus produces a similar amount of noise as its Gardner-engined It is too soon to give firm fuel consumption or performance figures for XF3. These are the subject of continued experiment, but Mr. J. T. R. Lewis, of the development section at Chiswick, who accompanied me on the trip, told me that first impressions had been quite favourable. The engine had been fitted for assessment, and to test the claimed American engine reliability. It has been set to develop 140 b.h.p. at 2,000 r.p.m.

The bonnet has been extended 71 in. to accommodate the engine, although (as an illustration shows) it looks "lost" compared to a Gardner 6LX installation. The spaciousness inside the bonnet may well have added to the impression of quieter running on the part of the Cummins engine.

One-man operation

Turning now to the one-man operation of the bus: The "pay as you enter" sign was displayed at the front and side of the vehicle and most passengers were prepared to pay the driver as they boarded. The district chief inspector, who travelled with me, admitted that some passengers were a little confused when onemanning was first introduced, but most of them had now accepted the idea that during off-peak periods no conductor was employed: Most of the way the traffic was relatively light, as the service passes through much open country, but passing through Horley the bus became quite busy, although the supply of seats available on the lower deck (31) was never fully exhausted.

During my previous trip when a conductor was carried, a total of five women passengers boarded at one stage or another with small children and push-chairs and I was interested to see how such passengers would cope without the help of a conductor. On this occasion, however, only one woman with a push-chair was encountered. She had two children with her and I restrained the inspector from his natural instinct to go to her aid, to see how she would manage unaided.


First of all she put down her push-chair and sent the children into the saloon while she paid the driver. Then she picked up the push-chair, climbed the step into the saloon and, depositing the chair in the shelf over the nearside front wheelarch, went on to join the children. The whole operation took little more than 60 seconds. It would obviously have been easier for the mother had there been a conductor there to help her, but if essentia economies have to be made, then some of the personal servic( must inevitably be sacrificed.

On arrival at East Grinstead the flexibility of operatior employed on this route was demonstrated. By now it was luncf time and a minor "peak" was being encountered. At a stof adjacent to East Grinstead garage, on the approach to the towr centre, another driver boarded the bus and the driver/conductoi who had brought us from Reigate relinquished his role of driver unlocked the door leading to the staircase and assumed the rol( of normal conductor.

Passing through the centre of East Grinstead and on toward! the Stonequarry Estate to the north-east of the town, the usefulness in this change from a one-man "single-decker" to e crew-operated double-decker was admirably illustrated. The firsi driver would continue his conducting role on the return trip from the estate through the town until Fellbridge was reached on th( western outskirts of East Grinstead. Here he would again lock du door to the upper saloon, leave the bus to continue as a one-mar vehicle back to Reigate, and take-over the conducting of anothei Fleetline heading for East Grinstead.

Close scrutiny of loadings

Frequent reports of anticipated loadings are passed from inspectors to the garage and if an unexpected peak is anticipated a relief driver or conductor can take over a bus in the manner already described. London Transport reports that it is satisfied with the way the 424 service experiment has gone and furthei experiments on similar lines can be expected.

As I see it the next step is to go the whole way and operate th( buses as one-man vehicles with the top-deck open in off-peaks This would eliminate the need for the elaborate, if successful lunch-time two-manning, even if conductors were still carriec during the morning and evening peak hours.

I think the day of the one-man double-decker has definitel3 arrived, and perhaps we will see the delivery of some more rear engined Routemasters for further operations of this nature in tin London Transport country bus area.

Come On, You Guys !

you really can't help some people. Operators are not slow to criticize manufacturers for what they conceive to be shortcomings in vehicle design or delivery, yet when someone in the manufacturing industry leans over backwards to help operators, what do they meet? Appalling apathy, it seems.

In recent weeks Guy Motors, at considerable cost, has been inserting full-page advertisements in the transport Press asking operators of Guys to fill in and send to them a simple form showing the vehicles which may need conversion kits to meet the brake regulations which come into force on January 1 1968.

Guy estimates that there are around 6,000 operators of their vehicles which may need kits, but they need to have a clearer idea of the likely demand before they make production plans to meet it. How many operators do you suppose have responded? Just 40.

And if at the end of the year there were insufficient kits to meet conversion needs on Guys, who would complain the loudest? My guess: the other 5,660.

No need for me to draw the obvious moral, surely, but simply to drop a hint about New Year resolutions. .

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