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N-Trizzy2609

Top Contact Vs. Bottom Contact Third Rail, Your Thoughts?

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It seems like after a MTA work fired herself recently in tragic incident with coming into contact with 3rd Rail in the subway, there been a debate going on about Top Vs. Bottom. Which one is better? Which one is more benifical? Which one works better under serious conditions? This tread is to debate over the different 3rd rails. Since MNRR uses bottom contact, it only right I post here. And please no flame wars and if I hear the words R179 or R188. This will be reported and closed.

 

I personally prefer Bottom Contact over Top because it less of chance getting fired and workers won't have the possibility or getting shock as bad as top contact. Plus it's less of a chance of get fried if there a puddle around the rail.

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The shock would be the same, depending on the current going through. And the contact surface is on the bottom, which would face towards a puddle, Top contact would face away from any puddles, no?

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Top contact is much safer out in the open, if a tree falls on it, not much happens, bottom contact is much taller off the ground, if it's damaged trains can't pass the damaged area because it would "fall" vs top just losing contact in the impacted area. If you fall in a tunnel, the risk of shock by 3rd rail is going to be there no matter what kind you have. I think top contact is easier to work on also, because it rests on insulators vs suspended. As far as puddles, i'd be more concerned with the feeder cables than the 3rd rail itself, since they typically run along the ground.

 

I myself would prefer overhead AC to 3rd rail.

 

- A

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It seems like after a MTA work fired herself recently in tragic incident with coming into contact with 3rd Rail in the subway, there been a debate going on about Top Vs. Bottom. Which one is better? Which one is more benifical? Which one works better under serious conditions? This tread is to debate over the different 3rd rails. Since MNRR uses bottom contact, it only right I post here. And please no flame wars and if I hear the words R179 or R188. This will be reported and closed.

 

I personally prefer Bottom Contact over Top because it less of chance getting fired and workers won't have the possibility or getting shock as bad as top contact. Plus it's less of a chance of get fried if there a puddle around the rail.

 

What incident of a killed worker are you refeering to?

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Top contact is better both in terms of efficiency and speed (100-110 mph vs 60 mph on bottom contact).

 

 

I myself would prefer overhead AC to 3rd rail.

 

- A

 

FTW! AC>DC. 25Kv/60Hz!!!

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I think the third rail should be respected at all times, top or bottom contact. I admire the job our P.D. Men do in maintaining the third rail.

 

Interestingly, London Underground uses a four rail supply. The third rail is 420 volts and the center return rail is 210 volts. Together, both rails equal 630 volts.

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I think the third rail should be respected at all times, top or bottom contact. I admire the job our P.D. Men do in maintaining the third rail.

 

Interestingly, London Underground uses a four rail supply. The third rail is 420 volts and the center return rail is 210 volts. Together, both rails equal 630 volts.

 

The outer rail i believe is the "dangerous" one.

 

- A

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The outer rail i believe is the "dangerous" one.

 

- A

 

That's right! The funny thing is that they build what they call a "suicide pit" right below it so anyone that tries to commit suicide would fall into the pit. Ironically either way, the person wouldn't get saved by pit if they land on the center rail and would consequently get sliced in half. I bet that if any person were to do so, they would definitely land on the center rail.

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All things being equal, of the ground electrification types i am partial to the conduit/plow, which keeps the electrical infrastructure totally away from any person, and can be used in open, tunnel, viaduct or street running. Using a 3rd and/or 4th rail located in the conduit a foot and a half under the tracks. The only real downside is the initial construction, which entails excavation on streets. It is how several trolly/tram systems ran, and what i think may work very well in the future in some, but not all locations. Locations not suitable for conduit should be considered for trackless or tracked trolly.

 

The issue at hand for main line 3rd and 4th rail systems is speed, you can't go over 100 mph in most cases, even if you wanted to, so overhead again is a wise choice, especially over long distances.

 

- A

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