Trains and buses crap NVH
Discussion
Having dropped the car off at the garage, I'm getting an "appreciation" of trains and buses.
Question to train and bus engineers of the forum. Why do buses and trains have noise vibration and harshness that wouldn't be tolerated on even the cheapest or most agricultural car?
In theory larger vehicles should ride better due to larger wheels, wheelbase and ratio of vehicle mass to unsprung mass.
I'm assuming that the route of this is that cars are generally bought by the person that rides in them!
Question to train and bus engineers of the forum. Why do buses and trains have noise vibration and harshness that wouldn't be tolerated on even the cheapest or most agricultural car?
In theory larger vehicles should ride better due to larger wheels, wheelbase and ratio of vehicle mass to unsprung mass.
I'm assuming that the route of this is that cars are generally bought by the person that rides in them!
...because trains and buses are built in much smaller numbers by several orders of magnitude and are not subject to the same rate of development and refinement that cars are, or at least the design iteration rate is much less frequent because of the capital costs involved in prototyping.
Also, ticket holders get off the bus or train at the end of the journey, whereas car owners take their buyers remorse to bed with them...
Also, ticket holders get off the bus or train at the end of the journey, whereas car owners take their buyers remorse to bed with them...
They operating companies aren't in it to provide the highest quality service possible, they are in it for the money, and to move as many people around as cheaply as possible. Even so, a lot depends on the sort of train. Pacers were intended as a stop-gap measure and are based on buses. For cheapness and inherent problems with packaging they don't run on bogeys, so there is limited suspension. That suspension is also simple and low-tech, which makes for reliability and ease of maintenance. In theory anyway.
Similarly, buses aren't intended to be limos. Any extra money spent on vehicles with advanced suspension is effectively wasted, as those passengers were always going to travel with you anyway.
Similarly, buses aren't intended to be limos. Any extra money spent on vehicles with advanced suspension is effectively wasted, as those passengers were always going to travel with you anyway.
Despite being a nightmare for everything around them the bendy buses used in Brighton are relatively refined if you get one without too many rattles, especially near the front since the engine is so far away. The ride is good by bus standards too although the seats in them are utter crap. The double deckers are pretty terrible, and they feel quite a bit slower too.
posted so this comes up later when I have time to answer in detail. Jimbo. said:
Do all busses have a binary throttle and braking system that's primed to operate just as you're walking down the bus to your seat/the door? 
Bob Newhart's Bus Driver's School: https://www.youtube.com/watch?v=AobZe6iT9kY
te though, so maybe not a consistent approach.Jimbo. said:
Do all busses have a binary throttle and braking system that's primed to operate just as you're walking down the bus to your seat/the door?
Ok.
Firstly there's very roughly about 2000 buses built in the UK each year - so as alluded to above the level of development and testing (and the money available to spend on it) is far far lower than mass produced cars or vans.
Basically - the bus is a tool. Its job is to turn up on time, and not break down, all the while spending a minimum on fuel and maintenance. The maintenance of buses is intense, with regular (4 or 6 week) inspections, with annual MOTs from new (the MOT for a bus/PSV is far far more involved than for a car).
Binary throttle - no. In fact this a really big issue, and things like acceleration rate management are systems are used often. Many operators use 'driver scoring' based on things like smooth driving, fuel use etc and this is often related to drivers buses. Our vehicles automatically calculate a driver score based on all sorts of factors.
Much of the braking on a bus is done by the retarder, rather than the foundation brakes themselves, and smoothness of the braking is down to the drivers control and feel for these two systems.
TheFinners said:
The double deckers are pretty terrible, and they feel quite a bit slower too.
Do they have different double deckers in Brighton to the ones they send up to Tunbridge Wells? The ones that come through here on there way to T Wells always seem great and are comfortable enough whenever I have been on them, and they dont hang about. A lot better than the Arriva buses that come out from T WellsChrisgr31 said:
Do they have different double deckers in Brighton to the ones they send up to Tunbridge Wells? The ones that come through here on there way to T Wells always seem great and are comfortable enough whenever I have been on them, and they dont hang about. A lot better than the Arriva buses that come out from T Wells
In fairness, some do seem to have better seats which make a difference, so they may be the ones you get in T Wells.snotrag said:
Jimbo. said:
Do all busses have a binary throttle and braking system that's primed to operate just as you're walking down the bus to your seat/the door?
Ok.
Firstly there's very roughly about 2000 buses built in the UK each year - so as alluded to above the level of development and testing (and the money available to spend on it) is far far lower than mass produced cars or vans.
Basically - the bus is a tool. Its job is to turn up on time, and not break down, all the while spending a minimum on fuel and maintenance. The maintenance of buses is intense, with regular (4 or 6 week) inspections, with annual MOTs from new (the MOT for a bus/PSV is far far more involved than for a car).
Binary throttle - no. In fact this a really big issue, and things like acceleration rate management are systems are used often. Many operators use 'driver scoring' based on things like smooth driving, fuel use etc and this is often related to drivers buses. Our vehicles automatically calculate a driver score based on all sorts of factors.
Much of the braking on a bus is done by the retarder, rather than the foundation brakes themselves, and smoothness of the braking is down to the drivers control and feel for these two systems.
I believe coaches are much smoother/quieter but presume that comes at cost and for bus routes they just want something that'll soak up all the daily abuse the terrible roads and the chimps that drive the things can dish out, ie they're built to the same ideology as an 80's lada?
I'd love to know why the engines are so loud. Given the operate in many urban areas, they make a right racket and often seem to idle at just the right speed to resonate with all the windows and seats to rattle the whole bus.
HGV's seem to be infinitely more refined when it comes to engines.
HGV's seem to be infinitely more refined when it comes to engines.
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