I apologize if I'm posting in the wrong forum, for I can't find an appropriate one.
I was watching an old episode of "LASSIE" on television, and Lassie was caught on a railroad trestle as a diesel freight was crossing.
Lassie avoided being hit by the train by lying down next to a water barrel on the side of the trestle.
After the train passed, I noticed the tracks on the trestle.
There was an extra set of rails set inside of and parallel to the regular rails, and they ran the length of the trestle.
What was the purpose of those extra rails?
Do they have a special name?
Thank you.
Kairho Member # 1567
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writesong Member # 3566
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Kairho:
Thanks for responding.
But, if the trestle was designed to accommodate both narrow gauge and regular gauge, then why did the parallel rails on the inside go no further than the ends of the trestle?
How were narrow gauge trains supposed to get on the trestle if only regular gauge tracks led to it?
The mystery (for me) continues.
Just blame it on that ***, "LASSIE"!
Thank you.
writesong Member # 3566
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Gosh, gee whillikers, that's weird!
I called "Lassie" a "D" - "O" - "G", and the posting changed it to asterisks.
When did "D - O - G" become a profane word?
I guess we can call "Lassie" a collie.
Thank you.
George Harris Member # 2077
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The inside rail are guard rails. They are for the purpose of keeping the train from going off the side in case of derailment. In other words, in case the train derails the guard rail is to keep the wheel that derailed toward the inside from getting so far away from the rail that it was supposed to be on that the other wheel would drop off the end of the ties, resulting in the derailed train falling off the bridge. Depending upon the thinking of the railroad company, they can end either with the end of the bridge or up to about 75 feet off the end of the bridge. Usually at the ends the ends of the rails are brought together in a "V" at the center of the track. Normally the ends are either turned down adjacent to each other or connected to each other by a turnout frog. Usually the rails are older and lighter than the running rails. Most companies do not allow the guard rails to be higher than the running rails. The frog, if such is used, is normally one that is no longer usable in a turnout because of the wear. The outside "wing" rails of the frog are not there, so all you have is the point and heel.
That is the theory of how guard rails work. In practice it does not work so well. Generally if things have gone bad enough that the train has derailed it can also go over the guard rail as well. There was a number of years ago a passenger train derailment on a bridge where a piece of the guard rail punched through the bottom of the car and killed a passenger. There have been other cases where it was thought that the guard rail made the situation worse rather than better.
Therefore, guard rails are not universally used. As it has been said, some companies swear by them, other companies swear at them.
Part of the problem with guard rails is that, since they serve no purpose as long as the train is on the track their maintenance tends to be neglected, so they not be as well affixed to the ties as the company maintenance manual requires. The other problem is that they interfere with the operation of the tamper, so if the ballast is tamped the guard rails must be removed and replaced.
George
writesong Member # 3566
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George Harris:
Thank you for that explanation.
I see you are a civil engineer in Taipei, Taiwan.
That is a very interesting profile.
Isn't Taiwan currently constructing what will become the world's tallest building?
Do you work on Taiwan's railroads?
Thank you.
George Harris Member # 2077
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I am the alignment engineer on the Taiwan High Speed Railroad. Taipei to Kaohsiung, 345 km, (214 miles) about $15 billion US, 300 km/h (186 mph) but with the geometry to allow 350 km/h later. Since design work on the alignment part is finished, as is now almost all track construction, I am now dealing with clearance issues primarily and other alignment or track related issues that have come up during construction. The proposed opening date for the system is end of October this year.
The tallest building, Taipei 101 is diagonally across the intersection from our office. The structure is finished, most of the interior work is also finished and the first tenants are now moving in. The bottom four floors are a shopping mall which has been opened for about six months. In the basement is a food court which is the lunch destination of about 2/3 of the buy your lunch contingent in this office. When we have earthquakes, a goodly number of the people in our office run to the front windows to see what that building is doing.
George
Kairho Member # 1567
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Ah ha, I missed that those rails were only on the trestle itself. Obviously, George is correct. I'll edit my earlier response so as not to confuse/mislead future genrations.
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