TILTING TRAINS

CONTENTS

•         INTRODUCTION                                                                                                                      

•         WHAT IS TILTING TRAIN?                                                                                                    

•         WHY TILTING HELPS?                                                                                                          

•         HOW DO TRAINS TILT?                                                                                                        

•         COUNTRIES WHO DEVELOPED THE TILTING TECHNOLOGY                  

•         ADVANTAGES AND DISADVANTAGES                                                                                                                            

•         SUMMARY                                                                                                                                                

•         CONCLUSION                                                                                                                          

•         BIBLIOGRAPHY

INTRODUCTION

            Train is a mass transporter, which transports humans and goods from one place to another place. We have trains, which run by diesel and electricity. Among goods and passenger trains the most concerned one is passenger trains.

            The passenger train should move quickly with high speeds. The rail road will not be always straight it should pass through curves and turns. We all know that if you are driving in your car and you take a turning at speed you feel centrifugal forces. Well it is no different from trains, if a train takes a turning at speeds centrifugal forces will be experienced.

            The major problem for any trains is to pass over the curves and turns of the railroads. If the train moves with the same speed at the curves and turns the train may slip from the track, so the speed of the train will be slowdown drastically to avoid slip.

            This results in wastage of fuel and in turn reduces the speed of the train, which is main consideration for the passenger trains. One of the solution found to avoid this situation is the tilting trains

WHAT IS TILTING TRAIN?

            Tilting train consists of a tilting mechanism that enables increased speed on regular tracks.

 

            In the upper part of the tilting trains that is in which the passengers are seated can be tilted sideways. During the motion of the train if the train has to steer to left in a left turning the coaches of the train will be tilted to the left in order to compensate the centrifugal push to the right and conversely during the right turn.

 

            These trains are constructed such that inertial forces which cause the tilting can be controlled by a computer.

    

            If the trains travel at speeds more than the specified speeds at the turnings of the railway tracks their will be centrifugal forces acting on the train. Due to these centrifugal forces the train may slip and push out of the tracks. But in case of tilting trains which will not happen, because of the reason that centrifugal forces will be compensated by tilting mechanism.

WHY TILTING HELPS?

            When sitting on a corner going at speed there are two forces acting on you, gravitational force and the centrifugal force which is accelerating you into the corner. In physics when two forces act, then this causes a resultant force. The resultant force will push you into your seat and to the side. However if the train is tilting, then the normal contact force of you on your seat will be the same as the resultant force you are experiencing. This means as far as the passenger is concerned he or she is just being pulled into his or her seat, and he or she is used to that so no discomfort is felt.

            This is true also of aero planes, commercial planes tilt a large amount, up to 30 degrees when going around corners in some cases to cater for passenger comfort. As the tilting of the aero plane is to get rid of the problem of centrifugal forces, or more accurately to disguised the centrifugal forces as a part of gravity as far as the passengers are concerned. The only way you know if the aero plane is tilting is to look out of the window.

            Trains that tilt can go up to 25% to 40% faster around curves than conventional trains without upsetting the passengers, and as mentioned before this can significantly increase  average speeds and cut journey times.

HOW DO TRAINS TILT?

            Carriages have tilting mechanisms. Obviously the bogies cannot tilt because they ride on the track and must follow the path of the track. So the coaches have to tilt on the bogies. The way they do this is simple, the bogie acts a fulcrum in the center and it is free to tilt either side. Then pistons control how much the coach tilts. The pistons are controlled by a small computer, which uses a spirit level. The spirit level is used to check if things are horizontal remember, i.e. at right angles to the resultant force acting. Normally this force is gravity, but when going round a corner the resultant is a combination of gravity and centrifugal forces. This means the spirit level indicates it is no longer horizontal, so the computer adjusts the pistons until horizontal is read. Again this will not be horizontal to the ground, but as far as anyone on the train is concerned it will be horizontal, keeping the passengers happy.

 

            In the early days they tried to use inertial force to let the trains tilt… i.e. they would have no mechanism to make them tilt but the carriages would have a low center of gravity so centrifugal forces on the carriage would cause them to tilt. This proved unsuccessful

COUNTRIES WHO DEVELOPED THE TILTING TECHOLOGY

•       Britain

•       France

•       Spain

•       USA/Canada

•       Sweden

•       Switzerland

•       Germany

ADVANTAGES AND DISADVANTAGES

ADVANTAGES

 

•         Fuel consumed by the trains can be minimized.

 

•         Speed of the trains can be maintained constant and hence time to reach the destination is minimized

 

•         Their will be Comfort ness for the passengers.

 

DISADVANTAGES

 

•         Very costly to manufacture these kind of trains.

 

•         If the coaches do not tilt then it is dangerous.

 

SUMMARY

            While the Very high speed trains like the TGV could be regarded as the Rolls Royce of trains, tilting trains could be thought of as the cheep and cheerful mini metro. The price differential is fairly similar too, it costs about 20 times more per unit distance to build a dedicated high speed line than it does to upgrade existing lines for tilting trains. This is what makes tilting trains extremely attractive. However there are disadvantages. 140mph or 230km/h is about as fast as trains go when not on dedicated lines. And then they have to be fitted in with slower moving traffic.

 

            With rail travel growing all over Europe, the problems of railways reaching saturation point has forced new lines to be build. This is why despite the success of the Italian Pendolini a new high speed line with 300 km/h trains is being built, because existing lines are at saturation.

CONCLUSION

•    The tilting trains can be considered as the cheerful mini metro trains.

 

•    To construct high speed lines it costs about 20 times more per unit distance than to upgrade existing lines for tilting trains.

 

•    Tilting trains can go up to 25% to 40% faster around corners than conventional trains without any discomfort ness to the passengers.

BIBLIOGRAPHY

Books:

 

•   R.S.Khurmi, “Theory of Machines”, Inertia Forces and Resiprocating parts Pg.No.496-540, Gyroscopic Couple Pg.464-495.

•   V.A. Profilldis, “Railway Engineering”, Chapter.5 , Pg.No.105 to 115.”

 

Websites:

•   www.googlesearch/tiltingtrains.com