[Transsenger]

Hey Raj_5004...next time checkout the new IrizarTVS coach "iT09". Let people here have an opportunity to experience somthing different other than the usual P8000 buses in kerala!

[raj_5004]

can you give me a link to that please?

chk these pics



















this is the link to the album just in case u want to see it more clearly
http://s1009.photobucket.com/albums/...0TVS%20Irizar/

[raj_5004]

thanks for the links buddy. is the bus launched? any idea on the variants & pricing?

Originally Posted by raj_5004

thanks for the links buddy. is the bus launched? any idea on the variants & pricing?

AC variant 22 lacs...non AC 12 lacs yes they have launched do you wantt o get int ouch with someone in TVS for this

[raj_5004]

No santosh, we do have contacts in AL but do they provide a mini bus, as in, 25 seater or 30 seater AC version?

and are you serious? AC variant for 22 lakhs? we just got our 49 seater NON-AC bus for 22 lakhs!

Originally Posted by raj_5004

No santosh, we do have contacts in AL but do they provide a mini bus, as in, 25 seater or 30 seater AC version?

and are you serious? AC variant for 22 lakhs? we just got our 49 seater NON-AC bus for 22 lakhs!

it is 22 lacs minus chasis and 14 lacs non ac...i will enquire if they do make a 25-30 seater version

raj heard APSRTC has launched AL Irizar buses on Hyderbad Bangalore route can youc heck with your sources if the Luxura has started rolling out

[Ashley2]

Originally Posted by santoshnair

raj heard APSRTC has launched AL Irizar buses on Hyderbad Bangalore route can youc heck with your sources if the Luxura has started rolling out

AL has given Luxura's to APSRTC long back.But I am yet to see a photograph of that ...

[r_nairtvm]

Originally Posted by Sankar

Can someone tell me why heavy vehicles use air-brakes instead of hydraulic braking systems found in cars and light commercial vehicles? What are the benefits of having air brakes?

Originally Posted by pjbiju

From what I know, trucks, trains and other large vehicles use air brakes.

Air pressure is used to release the brakes and hence until the required pressure is built up, the brakes would remain engaged. This is the opposite of hydraulic brakes where hydraulic pressure is used to engage the brakes.

Originally Posted by BaCkSeAtDrIVeR

I am afraid that this is not entirely accurate.

But my 1978 model AL had air brakes, and it was pressure actuated, NOT vacuum brakes. A small leak anywhere in the circuit and brakes would malfunction.

Shankar, a cheeky answer if you like

Air is everywhere. Hydraulic fluid isn't.

But really not cheeky

The heavier forms of transport - Trains, buses and tractor-trailers - use air-brake systems so they don’t have to rely on the hydraulic fluid (which may not be there) in car braking systems, which can run out in the event of a leak.

The first air barking systems introduced were - direct air-brake systems, which used an air compressor to feed air through a brake pipe into air tanks on each car. When the engineer applied these brakes, the pipe filled with air and squeezed the brakes. (These were the systems that the Backseatdriver has stated was existing in our heavy vehicles until 1980s)

Actually the vacuum based system was introduced in 1869, an engineer named George Westinghouse realized the importance of safety in the relatively new railroad industry and invented the first triple-valve air-brake system for railcar use.

Westinghouse’s system worked the opposite way of a direct air-brake system. The triple-valve system performed three functions, thus its name (This is what the system pjbigu has stated as in use in today’s heavy vehicles)

Charging: The system must be pressurized with air before the brakes will release. At rest, the brakes remain engaged. Once the system reaches its operating pressure, the brakes are freed and ready to use.
Applying: As the brakes are applied, air pressure decreases. As the amount of air decreases, the valve allows air back into the reservoir tanks, while the brakes move to the applied position.
Releasing: Once the brakes are applied and the air escapes after braking, the increased pressure releases the brakes.

Now when/how the change came about

In US of A in the 1970's truckers were dying whenever they lost air pressure heading down steep mountain grades. The Department of Transportation and the Federal Bureau of Motor Vehicles Safety Division changed the requirements for air brake systems on all motor vehicles.

The Direct Air Brake Systems would not work if there was a loss of air. Truckers would have a runaway truck on their hands. As per the federal intervention in the late '70s or early '80s the engineering of these brake systems was reversed (functionally almost similar to the Westinghouse System)

Now when air brakes are applied, there is a valve that receives the applied air pressure. When the valve begins to open, it releases stored air pressure that is being held inside a chamber. That chamber has a heavy spring inside of it that begins to apply brake pressure in the absence of air pressure. Now when a trucker loses air pressure on a mountain grade, the spring will apply fully to lock up the brake shoes against the brake drum, preventing (hopefully) a runaway truck/bus.

This was further refined with dual tanks and dual circuits, ABS etc.

Shankar - The air brake is not there (commonly) in cars due to the practicality and requirement of it. Cars have relatively smaller mass and even in case of a complete brake failure can be controlled with the engine braking and use of gear box, hand brake etc. The mass of a cra will not give it sufficient momentum to acheive the the proportions of a runaway truck/bus Also we really have not heard of a runaway car. The worst runaway bus I can remember in Kerala was the Elappara one in the mid 1980s).

Now with many cars having independent circuits for front & back or diogannaly the barking system has enough redundancy built in (I hope so). Hence no air brakes in cars

Hope you would find this to be useful

Raj – the buses look lovely and all the best with the venture and wish you a very long and fruitful ownership of them.

Best Regards & Drive/Ride Safe

Ram

[BaCkSeAtDrIVeR]

Thanks for the lovely explanation on air brakes.

Coming to think of it, the Indian railways changed over to vacuum brakes from pressure brakes within the past decate. Even 5 years back, locomotives aka "engines" used to have the "dual braking system" written on them. FWIW, the brown coloured coaches were pressure brakes, the blue coaches have the vacuum brakes.

[raj_5004]

Originally Posted by r_nairtvm

Raj – the buses look lovely and all the best with the venture and wish you a very long and fruitful ownership of them.

Best Regards & Drive/Ride Safe

Ram

thanks a lot r_nair (even i am R. Nair!). by the way, i do not drive the bus!

[theMAG]

Originally Posted by raj_5004

by the way, i do not drive the bus!

You probably should, even if its a small spin. If anything, it would be educational. If I had access to a Volvo bus, I would have loved taking it for a spin !

[r_nairtvm]

Originally Posted by raj_5004

thanks a lot r_nair (even i am R. Nair!). by the way, i do not drive the bus!

Raj

That is my signature sign off.

By the way I have a heavy license and I can drive a truck or bus and have done both whilst I was in India.

As theMag said you should get your Heavy and experience driving your bus. It will the laest help you to understand what your Drivers would be talking about. Driving a heavy is totally different experience from driving a car or bike.

All the best

Best Regards & Drive/Ride Safe

Ram

[raj_5004]

Originally Posted by theMAG

You probably should, even if its a small spin. If anything, it would be educational. If I had access to a Volvo bus, I would have loved taking it for a spin !

i have driven it but taken it out for long drives.

Originally Posted by r_nairtvm

By the way I have a heavy license and I can drive a truck or bus and have done both whilst I was in India.

As theMag said you should get your Heavy and experience driving your bus. It will the laest help you to understand what your Drivers would be talking about. Driving a heavy is totally different experience from driving a car or bike.

All the best

Best Regards & Drive/Ride Safe

Ram

the reason why i dont have a heavy license is because kerela's law demands that i have to transfer my mumbai license to kerela before i can get the heavy license there. alternatively, i have to apply for a new license there & wait for 3 years before i can get a heavy license.

[BaCkSeAtDrIVeR]

Originally Posted by raj_5004

the reason why i dont have a heavy license is because kerela's law demands that i have to transfer my mumbai license to kerela before i can get the heavy license there. alternatively, i have to apply for a new license there & wait for 3 years before i can get a heavy license.

You are not supposed to hold two licenses, irrespectiv of state of issue.

You can take a license in Mumbai itself.