[condor]

Guys, is the rear /3rd axle of vestibule buses of a slightly floating nature ? Happened to notice one bus when it was turning left, and the 3rd row wheels/axle seemed to point slightly in the opposite direction.

I was driving, so could not really notice it closely enough. Keep an eye out, will ya ?

[Ashley2]

Originally Posted by condor

Guys, is the rear /3rd axle of vestibule buses of a slightly floating nature ? Happened to notice one bus when it was turning left, and the 3rd row wheels/axle seemed to point slightly in the opposite direction.

Yes you are right!
They are steerable.

[condor]

@Ashley, thanks.

Considering the focus in these buses on cost effectiveness, I dont think these are actually "steerable". The implementation may be something simpler & mechanical in nature and not very sophisticated.

Would you have any details of how it is implemented in these buses ?

[arvi86]

Originally Posted by condor

@Ashley, thanks.

Considering the focus in these buses on cost effectiveness, I dont think these are actually "steerable". The implementation may be something simpler & mechanical in nature and not very sophisticated.

Would you have any details of how it is implemented in these buses ?

I too think Ashley is right. By steerable, I think when taking a big turn, like a U-Turn for example, the rear most wheels turn in the opposite direction of the front wheels. I have noticed it in close quarters in Chennai CMBT terminus. But I too don't know about its working mechanism.

Since you have started the topic of Vestibule Buses, being a big fan of them, I would like to attach a picture of the Ashok Leyland Vestibule Bus of TNSTC Trichy.

[julupani]

I seriously doubt the rear most axles being steerable, considering the length of those buses, the fact that they would have to turn in the opposite direction and that the lengthened part is not exactly rigidly attached to the front.

The last reason is also probably the reason why the rear tyres looked to be moving in a different direction. Just like in a train on a turn, the front axle may be moving in a completely different direction than the rear most axle. A similar thing on a smaller scale is the case with these buses.

[MileCruncher]

APSRTC has included some TATA Marcopolo AC buses in Hyderabad. These are the same pattern as the DTC buses. Previously the Hyderabad had Volvo 9400 but don't seem to prefer them unlike BMTC.

[silversteed]

Originally Posted by condor

Guys, is the rear /3rd axle of vestibule buses of a slightly floating nature ? Happened to notice one bus when it was turning left, and the 3rd row wheels/axle seemed to point slightly in the opposite direction.

I was driving, so could not really notice it closely enough. Keep an eye out, will ya ?

I have kept a keen eye on these buses during my Chennai days. The wheels in the rearmost axle turn in the opposite direction as that of the front wheels, probably facilitated by some fairly simple mechanical linkages.

I think Ashley2 meant the above, when he said they are steerable.

MTC has a lot many of these buses plying between Thiruvanmiyur and Tambaram - not many twisties on that road, so it's easy for these vestibule buses to run. I once witnessed a less-experienced driver trying very hard to reverse one of these buses inside the Tiruvanmiyur depot workshop.

[Ashley2]

Originally Posted by silversteed

...The wheels in the rearmost axle turn in the opposite direction as that of the front wheels, probably facilitated by some fairly simple mechanical linkages.

I think Ashley2 meant the above, when he said they are steerable.

You are right about that. They steer opp to the direction they make a turn.

Originally Posted by silversteed

MTC has a lot many of these buses plying between Thiruvanmiyur and Tambaram - not many twisties on that road, so it's easy for these vestibule buses to run. I once witnessed a less-experienced driver trying very hard to reverse one of these buses inside the Tiruvanmiyur depot workshop.

T51 - Vestibule buses taking a right turn to enter Tiruvanmiyur depot is a classical example. There are cases where even the buses make a U turn without even entering inside the depot. The road width will not be more than 25 meters.

[Mpower]

Originally Posted by Ashley2

You are right about that. They steer opp to the direction they make a turn.


T51 - Vestibule buses taking a right turn to enter Tiruvanmiyur depot is a classical example. There are cases where even the buses make a U turn without even entering inside the depot. The road width will not be more than 25 meters.

Does AL do the body building for the vestibules? How are the sales and what is the future trend?

[MileCruncher]

I think only AL makes vestibule buses. APSRTC also has quite a few of them running in Hyderabad.

[Ashley2]

Originally Posted by Mpower

Does AL do the body building for the vestibules? How are the sales and what is the future trend?

Attached a image which shows the Mega bus built on Vestibule platform. This is a low floor concept avatar of Vestibule bus.
Volume should be upto 400 to 500 buses/year.
Body is built by Suppliers only based on ALs design

[silversteed]

Will it be a low-floor bus, like the RE buses supplied to KeSRTC? Or, similar to the Viking SLFs?

[DWind]

Originally Posted by Ashley2

T51 - Vestibule buses taking a right turn to enter Tiruvanmiyur depot is a classical example. There are cases where even the buses make a U turn without even entering inside the depot. The road width will not be more than 25 meters.

In fact at the Tambaram end (the other end point of T51) they definitely need to take the U turn in Velacherry road, just before the level crossing as there is no bus terminus and all buses start from the road.

[Ashley2]

Originally Posted by julupani

I seriously doubt the rear most axles being steerable, considering the length of those buses,

Originally Posted by silversteed

... The wheels in the rearmost axle turn in the opposite direction as that of the front wheels, probably facilitated by some fairly simple mechanical linkages.

There will be a drag link connected to the rear axle which is coupled from the front drop arm. This will facilitate the steering of the rear axle. You could see this clearly near the turn table(which actually makes the swirl)

Originally Posted by silversteed

Will it be a low-floor bus, like the RE buses supplied to KeSRTC? Or, similar to the Viking SLFs?

The tractor will be similar to conventional one where as the trailor will have stepless entry.

[silversteed]

Originally Posted by Ashley2

There will be a drag link connected to the rear axle which is coupled from the front drop arm. This will facilitate the steering of the rear axle. You could see this clearly near the turn table(which actually makes the swirl)

That explains how the wheels turn proportionally with the front wheels

Originally Posted by Ashley2

The tractor will be similar to conventional one where as the trailor will have stepless entry.

So, which one will be longer ie.,higher seating capacity - the tractor part or the trailer? And will there be air suspension in the trailer, and at least the rear axle of the tractor?