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Questions tagged [braking]

11 questions
18
votes
3 answers

Why do heavy trucks use air brakes?

I was having a discussion today, which led to the question why do heavy trucks still use air brakes? To my knowledge, it has been used for at least 40 years (I remember that as a kid), and apparently (I was told today but I haven't gotten around…
NMech
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6
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5 answers

Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

When waiting for the underground, I've always been wondering why we could not absorb the kinetic energy of the train to slow it down at the station and then to release this energy to help it accelerating during the starting up. This would also…
Noil
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6
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5 answers

Ways to brake an axle

I am currently studying Mechanical Engineering and am doing an assignment where I have to design a wire rope tensioner where a wire rope is unspooled from a drum, but the wire has to be at a specific tension when unspooling. Therefore I am looking…
David
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4
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7 answers

Why can't trains stop in 2x the distance of trucks from the same speed?

I recently learned that every axle on a modern train has brakes. In the past, I had assumed that only locomotives and cabooses had brakes, and assumed that was the reason for the commonly known long stopping distance of trains. This new discovery…
Azendale
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1
vote
2 answers

Is it normal for freight trains to require an external braking mechanism?

Today I heard a claim that the recently derailed train in Ohio was physically incapable of stopping except at its normal stops. I am skeptical of that claim because: Normally a vehicle contains whatever hardware it needs to stop. Cars have brakes.…
James Strieter
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1
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0 answers

Force necessary to resist motion due to torque on a drum brake

A drum is subjected to a counterclockwise torque of 16 in-lb. What horizontal force is necessary to resist motion? Coefficient of friction = 0.40 Weight is neglected. I'm having a hard time on this one. I've tried to separate the torque into a…
KDGH
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Does westinghouse braking system prevent using anti-lock system?

This question concerns the Westinghouse braking system. If I understand correctly this video, in an emergency braking (e.g. in case of failure in main air pressure line) the pressure in the main pressure line decrease rapidly (main pressure line…
Manu H
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0
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0 answers

Any information on magnetic braking with copper?

I have an engineering project where I have to design and build a model of a drop tower from a theme park. The tower itself can be no taller than 40cm. I plan to use magnetic braking with copper to stop the ride at the bottom. I intend to have the…
18jbrana
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0
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1 answer

How to model a driver's appropriate braking for deceleration, and throttle for acceleration for a car moving on a straight road?

A project team within my company is stuck on a conundrum and have asked me for some insights. They want to develop a driver model (mathematical or drawn) where input is the car's velocity profile, and the output is the braking (for deceleration) or…
Balaji Harihar
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0
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2 answers

What will be the force F for the given brake system?

I am getting two ways to find F. One is Fx0.2=30 Nm which gives F=150N Other is Fx0.2-640x0.13=0 which gives F=416N I am confused which one is incorrect. I know problem is too basic but still not clear where I am wrong. Question is shown in picture.…
Shivam Goswami
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Way to keep object on linear rail in the position you leave it in despite smaller external forces?

Problem: I have a rod on a linear rail system. This rod can be pushed forward or backwards. There is air blowing out of the front of the rod (~2 lbf) causing it to move to the back position by default. I am wondering if a mechanism exists that will…
Andrew
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