ADUK Archive

On a recent assessment drive I was criticized for making a gear change before a number of hazards. The scenario is that I am driving a coach along a flat piece of road in fifth gear at the 40mph speed limit, I have spotted in the mid-ground a short slope with a 30mph limit change, some islands and other features of small town centre including parked vehicles significantly reducing the roads width. I had decided that to make good safe progress, I would proceed at 40mph for the first half of the slope which could be maintained by selecting fourth gear which is also required when I enter the 30mph limit which I would reduce to using light use of the service brake whilst entering the congested town centre with a flexible gear already engaged. I selected fourth before the hill engaging with the engine revs matched for a smooth gear change which prevents the associated clutch were encountered with a brake-gear overlap whilst giving me less to do entering the series of hazards in the coaches path.
I was asked if I meant to change to the lower gear when I did, I responded with yes and brief outline of the description above. The response was "Just use the exhaust brake!".
Re living the scenario based on my memory I conclude that the exhaust brake would have likely held the coaches speed at 40mph during the short slope, I would have then used the service brake lightly to reduce to 30mph on the approach to the limit change but then see no alternative but to overlap the gear change with braking due to a slight gradient as the remainder of the hill flattens out at exactly the same point where the other hazards begin. I believe that this approach would have caused more mechanical wear, required a great deal more physical control use in a short space of time and giving me less control over developing situations.
To back up the view of my assessor who is one of the coach companies mechanics, the saying goes 'brakes to slow gears to go'. I used the gears initially to maintain a speed which shortly afterward assisted the brakes in speed reduction.
To further analyze some of my general driving practices, I always avoid brake-gear overlap when possible due to my Mini having a distorted clutch plate requiring a double-de-clutch and perfectly matched engine speed for a lower gear to engage and where there is no alternative to brake gear overlap I nudge the accelerator with the side of my right shoe.

In the world of PCV driving the only retarders I have used are the automatic type as fitted to automatic service buses with the best one being fitted to most Mercedes Benz O405's, these engage with the service brake at a light setting.

I would likely consider using an endurance brake for use on long descents, or in conjunction with a lower gear in slippery conditions, but even on a long descent I would likely use the endurance brake in conjunction with a flexible gear.


So the question is, with my first scenario what should I have done better?

I was imagining a truck in the same situation and would have done exactly what you did

Was that the only criticism? If there was nothing else quite likely the guy was just fishing for something to say. What you did sounds perfectly reasonable to me and I'd have been delighted to have someone prepared to justify their decisions in that way.

Although I've no PCV or HGV experience, it sounds to me as if what Andrew did was well considered and perfectly reasonable. I think people get their knickers knotted too readily (perhaps that's a slight exaggeration in this case) when things don't appear to conform with their particular ideas about how it should all be done.

Best wishes all,
Dave.

zadocbrown wrote:Was that the only criticism? If there was nothing else quite likely the guy was just fishing for something to say. What you did sounds perfectly reasonable to me and I'd have been delighted to have someone prepared to justify their decisions in that way.

There was slightly more namely, sticking to the speed limit rather than just increasing the speed to 50mph and selecting the highest gear, and using the mirrors too much for example every time I intent to adjust the steering and every few seconds on a strait section of multi-lane carriage way.
The result of all this was not seen to be relevant and I was given a positive review by the mechanic and I am now a full time spare coach driver with no contract or guaranteed hours and currently no bookings. If I get any work required offered I will take it for no other reason than to get some private hire coach driving experience.

Andrew,

I don't see anything wrong with what you described either. As for the other comments regarding over-use of the mirrors, just ignore. Many do not use their mirrors enough.

The important thing is that they are happy enough with your drive and you may get some work and further experience out of it. Well Done.

I must presume that your mechanic lives in the mountainous region of Leicestershire.

If anyone told me, "Brakes to slow and gears to go," I would stick 24 tonnes of milk in the back of a fridge trailer and get them to drive the rig from the summit of the M62 down towards Manchester

They would soon realise that the "blue band" on the rev counter is not an advert for margarine, but the point at which the exhaust-brake is working at its most powerful; way above the normal power band and just below the safe maximum engine-speed. To use that braking band, you need to drop down a gear or two.

The alternative is to get brake-fade on the way down, and to arrive at Shaw (near Oldham) at around 85mph.

'Service' brake - middle pedal?

'Exhaust brake' - engine braking?

But I presume there's more to it than that!


Kindest Regards,
Confused of motorcycling background

Horse wrote:'Service' brake - middle pedal?

'Exhaust brake' - engine braking?

But I presume there's more to it than that!


Kindest Regards,
Confused of motorcycling background

===========================

Service brake....middle pedal.

Exhaust brake....usually a button on the floor or a separate lever on the column; some switchable on the dash to link with service brake operation. Others have progressive switching between minimum and maximum braking.....useful on slippery surfaces or when towing an empty trailer.

It sounds complicated, but they all work on the same principle, unless they are electric retarder brakes, which were common on coaches.

Are retarders still fitted to coaches anyone? I only do old buses with crash gearboxes, so I'm well out of touch.

The coach I now drive mostly is 29 years old, the first High-liner imported into Scotland, and there is no synchro left on the gearbox, there is a button on the floor for the exhaust brake.

The newest Coach I have driven is a Van Hool Alizee, Volvo B12. The B12 has a button on the floor which engages the exhaust brake plus a stalk underneath the indicator controls which has 5 settings, one of which is automatic but I have not driven far in that 8 year old coach to figure out what everything does, actually I prefer driving the older coaches and the other drivers are quite happy with this as most of them hate driving the high-liner mainly due to its unique gearbox with dynamic gate and no syncho.

I spoke to another driver who claims that with the Volvo B12 most motorway driving can be done without using the pedals, just the cruise control and the retarder are sufficient in most situations. If I have to drive a modern coach I prefer to switch the cruise control off as I seem to be able to control the speed in a smoother fashion.

I have seen something called a Telma fitted to other operators older coaches which has a control which looks like a console mounted gearbox, I hear that with this system some drivers seem not to use brakes which in some cases results in them seizing due to lack of use.

What's wrong with what you did??? I think that that was the correct maneuverer.