Depowering Third Rail on the Prototype?

Mitch...I can't say for CTA but as far as I know LIRR and Metro North rail is always powered..

CTA's third rail is always active.  One inebriated guy was killed while whizzing on the third rail several years ago.

Individual sections can be turned off (isolated) for maintenance or accidents.  Exactly how I'm not sure.

A demand-based power up/down system would be extremely expensive to install and maintain.

Rusty

I agree with Joe. I believe that the rail is always hot. Either way I wouldn't get near it. Even if it was shut off, the substations hold residual power in the transformer windings which must be discharged to ground before anything is safe to work on .

They have enough problems already keeping trains running,  throw in a system of 700VDC relays and contactors and a whole new maintenance headache develops.

M. Mitchell Marmel posted:

I'm reasonably sure that third rail powered lines that run at grade (for example, parts of the CTA  and LIRR) don't keep the third rail constantly powered, as it would be something of a hazard. 

Nope. They are kept hot all the time. They are only a "hazard" for those who trespass on railroad property.

 So, how exactly do they turn the power on and off on demand?  

They don't. Sections are only turned off for maintenance in that area, or a mishap/derailment.

Inquiring minds want to know.   

Mitch 

Like HOT said, third rail or catenary in the US is always hot unless it's being maintained or removed/taken out of service.   When it's de-energized  for maintenance/service or removal, it's  power is locked out on the substation/control station end and then the device grounded as per a whole slew of electrical safety rules.  

Along many older third rail systems that run through residential areas (such as the NY transit systems or the ex-P&W SEPTA Norristown High Speed Line) there is nothing more than the cover boards over the third rail along an unfenced right of way.  

Anyone can walk up to it.   Or touch it if they so desire to be shocked by 600 volts and many hundreds of amps.

Rule292 posted:

Along many older third rail systems that run through residential areas (such as the NY transit systems or the ex-P&W SEPTA Norristown High Speed Line) there is nothing more than the cover boards over the third rail along an unfenced right of way.  

And sometimes, as in the case of the Laurel Line, not even a cover board.  Brrrrr.  

Which is why I was wondering about de-energizing.   Having an open rail live like that...  

Mitch 

I have been a follower of electric railroads and traction lines most of my life.in many of my books they mention power dispatchers or systems that power the overhead and third rail ahead of and behind movements  so that its only powered when there is traffic in that section. I am sure you can find examples of both ( controlled and on all the time) if you look.  Rick

Third rail electric transmission on LIRR, NYC, Laurel Line, etc., was installed a hundred years ago.  Until recently, parents warned their children of the danger of touching the third rail.  People have used common sense and left the third rail alone.  There was the occasional electrocution, but it usually involved mischief or inebriation.

We should be careful not to dumb this down.  It always has been, and still is, the responsibility of individuals to avoid contact with third rails, and to instruct children to do the same.

There are a couple of long-abandoned systems for trolley cars where towns didn't want "unsightly" overhead wire. They used stud contact between the rails with magnetic switches to power up - something like full-size Marklin, contact shoes and all.

http://www.historywebsite.co.u...nsport/electric6.htm

http://wpehs.org.uk/dolter-sys...t-current-collection

The idea didn't last long. Sticky studs electrocuted the occasional horse or pedestrian who put a foot wrong. http://tinyurl.com/omm4sm7

M. Mitchell Marmel posted:

And sometimes, as in the case of the Laurel Line, not even a cover board.  Brrrrr.  

 

The Laurel Line used both third rail AND overhead as needed.  They also installed safety fencing along at least some of the ROW.    

In NYC some of the trolley lines used a trough between the rails for the power rather than overhead wire, it was in some places in NYC and the Bronx I believe. 

I have never run across powered traction systems where they only put power on the third rail when a train is present, while it is possible, you could have where when a train is getting near the end of one power 'block' it turns the next one on, but I have never read about it anywhere, at least in this area. With the Subway system they don't even cut power when crews are working on the third rail (unless they changed that recently), because NYC transit operates 24/7, when they need to work on the power rail they do so with it live, because trains are running (the guys who worked on power maintainance were proud of that, friend of mine in grad school was a senior EE with the TA, said those guys were certifiably proud (and crazy. 

Basically as others have pointed out third rails have cover boards over them, but doesn't matter on grades, at crossovers and such, they never have the rail unpowered. I don't know if it is true, but someone told me a while ago that MTA and the LIRR never power down the third rail even overnight when they aren't running trains, according to this person (how he 'knew' this I don't know), because they are afraid that if they turn it off weaker parts of the track circuit may oxidize and fail to power up again. I don't know if the cause is true, but I am pretty certain they don't shut it off overnight even though no trains are running. 

I have heard stories about foolish young men who would jump off a tree or a bridge at the height of catenary, and hang from the overhead catenary wires back in the early days of transit, showing bravado, and then would drop down from the wire to the ground, swinging out to land on the relative soft embankment rather than the rails. I don't know if that was a cautionary tale or really happpened (knowing how stupid many young guys tend to be, I can believe it). Kind of like the idiots diving off the Brooklyn Bridge, makes you wonder. 

bigkid posted:

In NYC some of the trolley lines used a trough between the rails for the power rather than overhead wire, it was in some places in NYC and the Bronx I believe. 

I have never run across powered traction systems where they only put power on the third rail when a train is present, while it is possible, you could have where when a train is getting near the end of one power 'block' it turns the next one on, but I have never read about it anywhere, at least in this area. With the Subway system they don't even cut power when crews are working on the third rail (unless they changed that recently), because NYC transit operates 24/7, when they need to work on the power rail they do so with it live, because trains are running (the guys who worked on power maintainance were proud of that, friend of mine in grad school was a senior EE with the TA, said those guys were certifiably proud (and crazy. 

Basically as others have pointed out third rails have cover boards over them, but doesn't matter on grades, at crossovers and such, they never have the rail unpowered. I don't know if it is true, but someone told me a while ago that MTA and the LIRR never power down the third rail even overnight when they aren't running trains, according to this person (how he 'knew' this I don't know), because they are afraid that if they turn it off weaker parts of the track circuit may oxidize and fail to power up again. I don't know if the cause is true, but I am pretty certain they don't shut it off overnight even though no trains are running. 

I have heard stories about foolish young men who would jump off a tree or a bridge at the height of catenary, and hang from the overhead catenary wires back in the early days of transit, showing bravado, and then would drop down from the wire to the ground, swinging out to land on the relative soft embankment rather than the rails. I don't know if that was a cautionary tale or really happpened (knowing how stupid many young guys tend to be, I can believe it). Kind of like the idiots diving off the Brooklyn Bridge, makes you wonder. 

I don't know if this is similar.  I've seen documentaries about working on the high voltage, high tension power lines.  The electrician is wearing some sort of metal mesh coverall.  He's lifted to the wires with a helicopter.  The seat or working platform he is on gets hooked to the wire.  I also believe, if memory serves, that his coverall has an attachment to the wire.  Now he's free to do his job without fear of electrocution.  

Way back in 1984, I was running a job in South Philly.  We were putting on an addition to a food storage warehouse.  Because the footprint of the addition ran over the high pressure gas line, the gas line had to be relocated.  So in comes PECO.  They dug down to the main, welded a saddle onto it.  Remember, the gas main is still live !  Then with a unique piece of equipment, drilled into the main and seated a Tee valve all at the same time.  They did this in two places and then ran a new pipe connecting them.

To show you how much faith I had in the guys that mark underground utilities, we had to dig down along side a 4000 volt conduit for our new grade beam.  Before any digging started, I drilled post holes with a post hole auger as close to the conduit as I thought I could get.  We sunk 4 x 4s in the holes.  Then the backhoe did his thing, keeping away from my posts about a foot.  After he was done we had to clean up the sides of the trench by hand.  It turns out my 4 x 4s were six inches from the side of the conduit.  Faith or just being young and dumb, I don't know.

M. Mitchell Marmel posted:

   So, how exactly do they turn the power on and off on demand?

Modern day conduit systems, pioneered in Bordeaux in 2003 and since applied at other French cities and exported, do just that;  each car turns on the power in the relatively short electrical block in front of it, turning it off behind them.  Some of these systems only use conduit in the city center zone, and overhead or battery elsewhere.   A search for, say, "Bordeaux conduit APS" will provide more details.

Best regards, SZ

Rule292 posted:

Along many older third rail systems that run through residential areas (such as the NY transit systems or the ex-P&W SEPTA Norristown High Speed Line) there is nothing more than the cover boards over the third rail along an unfenced right of way.  

Anyone can walk up to it.   Or touch it if they so desire to be shocked by 600 volts and many hundreds of amps.

When I was in college and living in Brooklyn, I would catch the Brighton Line at the Avenue M station (the subway was elevated at that point). On a regular basis, you would see a track worker walking on those cover boards while inspecting the tracks. It got scary (to me as an observer) when I'd see the board bend under the worker's weight   

Apples55 posted:

Rule292 posted:

Along many older third rail systems that run through residential areas (such as the NY transit systems or the ex-P&W SEPTA Norristown High Speed Line) there is nothing more than the cover boards over the third rail along an unfenced right of way.  

Anyone can walk up to it.   Or touch it if they so desire to be shocked by 600 volts and many hundreds of amps.

When I was in college and living in Brooklyn, I would catch the Brighton Line at the Avenue M station (the subway was elevated at that point). On a regular basis, you would see a track worker walking on those cover boards while inspecting the tracks. It got scary (to me as an observer) when I'd see the board bend under the worker's weight   

The guys working on the third rail on the subway system used to deliberately lean on the third rail (they wore heavy rubber gloves) when they had guests/visitors, and enjoyed watching people squirm. To them it was no big deal, then again they and track crews and the like are used to working while the trains are in operation, other lines do it during the overnight hours when they shut down. 

M. Mitchell Marmel posted:

I'm reasonably sure that third rail powered lines that run at grade (for example, parts of the CTA  and LIRR) don't keep the third rail constantly powered, as it would be something of a hazard.   So, how exactly do they turn the power on and off on demand?  

Inquiring minds want to know.   

Mitch 

I have been hearing this canard ever since I was a kid. The third rail on the LIRR, the NYC Subway System and Metro North is "hot" 24 hours a day, 7 days a week unless it is powered off for an emergency or for repairs.

I suggest you all take my word for it and not attempt to verify it by touching said third rail.

On a side note, the third rail on the former Southern Railway lines in England has no protection boards, as is common practice on US lines.

Okay, here's my dilemma:  

The fictional Razorback Traction Company operates over the former Frisco main line between Monett, MO and Fort Smith, AR (today's Arkansas and Missouri), as well as various connecting short lines that have been abandoned in real life.  The line is electrified with a combination of trolley/pantograph catenary on/near the main line  and outside third rail going back into the more remote areas (third rail being easier to install and being more robust than overhead).  Since the remote lines might only see one or two trains a day, there's no real need of the power being on 24/7 and, if the power is on, there is the danger of local wildlife and/or the sparse but existing population accidentally electrocuting themselves.   

Given the general setting (1930s-1940s), what would be a simple method for switching sections of third rail on and off automatically,  as well as indicating when the third rail is live?   What I'm thinking is something along the lines of the Nachod signaling system, wherein a train entering a block will energize the block ahead and de-energize the block behind, and signal lamps atop the protection boards would light when the block was live.  

Thoughts? 

Mitch

"Thoughts ? "     Well, since you asked......

1.  If these branches serving  remote areas see only one or two trains a day, why would they have been electrified in the first place ?  Either the capital costs of the electrification or the maintenance costs, let alone both, would probably not justify electrification or its continued usage.  So....

2.  An interurban of that era would probably have used a gasoline powered railbus or small loco on the branch, connecting to the mainline trains, assuming the line survived at all;  freight traffic would help here.  One might have a combine [ with the mail and express ] switched into and out of the through trains, to add some modelling possibilities.

3.  Other possibilities, for someone who might like to 'create' things [ if you know anyone like that...]  would be

   A.  A dual powered doodlebug that could MU with the electric interurbans on the main

   B.  A generator trailer that could be attached to an electric car to power it on the branch.

4.  Now if there were a famous Hot Springs Resort at the end of the branch, even though the number of trains would be small, that would create the possibility of a through sleeper from St Louie, or even the occasional private car........

There ya go.....

SZ

PS  I think the intermittent third rail approach is perhaps less safe than on all the time.  Would this line of road be subject to the ICC [ = FRA in 1930's-speak ] ?

Steinzeit posted:

"Thoughts ? "     Well, since you asked......

1.  If these branches serving  remote areas see only one or two trains a day, why would they have been electrified in the first place ?  Either the capital costs of the electrification or the maintenance costs, let alone both, would probably not justify electrification or its continued usage. 

Well, the Swanson family of Fort Smith,  who own the RTC,  are wealthy from other sources.   And the Brunswick family, particularly Senator "Marryin' Sam" Brunswick from Springdale, make sure the RTC has friends in Washington, DC, particularly when it comes to damming up the White River to make a hydroelectric plant under a TVA-type arrangement to electrify the region...  

2.  An interurban of that era would probably have used a gasoline powered railbus or small loco on the branch, connecting to the mainline trains, assuming the line survived at all;  freight traffic would help here.  One might have a combine [ with the mail and express ] switched into and out of the through trains, to add some modelling possibilities.

The branch lines actually use old ex-NYC electric locos retired from Grand Central Station.   And, since roads at the time are few and far between,  the trains are fairly well patronized.  A train might be mail delivery, produce shipping, ambulance for serious illnesses...

3.  Other possibilities, for someone who might like to 'create' things [ if you know anyone like that...]  would be

   A.  A dual powered doodlebug that could MU with the electric interurbans on the main

The RTC does have dual powered locos, both diesel/electric  and steam/electric (inspired by Swiss steam engines run from the catenary during WWII)...

   B.  A generator trailer that could be attached to an electric car to power it on the branch.

4.  Now if there were a famous Hot Springs Resort at the end of the branch, even though the number of trains would be small, that would create the possibility of a through sleeper from St Louie, or even the occasional private car........

Actually, there IS Monte Ne, which is mostly submerged but is a popular summertime attraction because of the 'mermaids' who perform for visitors in glass bottomed boats...  

PS  I think the intermittent third rail approach is perhaps less safe than on all the time.  Would this line of road be subject to the ICC [ = FRA in 1930's-speak ] ?

Good question.  How much authority did the ICC have over short lines? 

Mitch 

You could go low-budget and build fences.

"The danger to the public from the use of the third rail is considerably less than is popularly supposed, and in view of the precautions which have been taken to safeguard the ignorant or unwary, the chance of accident is very small. At the Berlin and Hartford stations the third rail section is fenced in on both sides. "  http://www.catskillarchive.com/rrextra/3rail.Html

M. Mitchell Marmel posted:

 

 

M. Mitchell Marmel posted:

Okay, here's my dilemma:  

The fictional Razorback Traction Company operates over the former Frisco main line between Monett, MO and Fort Smith, AR (today's Arkansas and Missouri), as well as various connecting short lines that have been abandoned in real life.  The line is electrified with a combination of trolley/pantograph catenary on/near the main line  and outside third rail going back into the more remote areas (third rail being easier to install and being more robust than overhead).  Since the remote lines might only see one or two trains a day, there's no real need of the power being on 24/7 and, if the power is on, there is the danger of local wildlife and/or the sparse but existing population accidentally electrocuting themselves.   

Given the general setting (1930s-1940s), what would be a simple method for switching sections of third rail on and off automatically,  as well as indicating when the third rail is live?   What I'm thinking is something along the lines of the Nachod signaling system, wherein a train entering a block will energize the block ahead and de-energize the block behind, and signal lamps atop the protection boards would light when the block was live.  

Thoughts? 

Mitch

 

 

Steinzeit posted:

SZ

PS  I think the intermittent third rail approach is perhaps less safe than on all the time.  Would this line of road be subject to the ICC [ = FRA in 1930's-speak ] ?

Federal regulation isn't pertinent to this discussion as there was no agency with general authority over railroad safety before the FRA was created in 1968.  The ICC's main mission was economic regulation.

The ICC was named as the enforcing agency under specific acts such as the Power Brake Law.  They were also given some authroity over minimum standards for signal systems.  I don't recaqll if they were the agency chacking compliance with federal law about steam boilers.

To the extent that either ICC or FRA had asfety regulation authority, it applied to all railroads including short lines.

 

 

M. Mitchell Marmel posted:

Okay, here's my dilemma:  

The fictional Razorback Traction Company operates over the former Frisco main line between Monett, MO and Fort Smith, AR (today's Arkansas and Missouri), as well as various connecting short lines that have been abandoned in real life.  The line is electrified with a combination of trolley/pantograph catenary on/near the main line  and outside third rail going back into the more remote areas (third rail being easier to install and being more robust than overhead).  Since the remote lines might only see one or two trains a day, there's no real need of the power being on 24/7 and, if the power is on, there is the danger of local wildlife and/or the sparse but existing population accidentally electrocuting themselves.   

Given the general setting (1930s-1940s), what would be a simple method for switching sections of third rail on and off automatically,  as well as indicating when the third rail is live?   What I'm thinking is something along the lines of the Nachod signaling system, wherein a train entering a block will energize the block ahead and de-energize the block behind, and signal lamps atop the protection boards would light when the block was live.  

Thoughts? 

Mitch

 

 

On the Sacramento Northern the trolley wire was shut off on industrial sidings. When a car needed to be switched, the crew would open a wooden box on one of the poles and close a large knife switch.  When finished switching, they would open the switch and be on their way. One of the interurbans in the Rochester, NY area they did the same for a lightly used branch line.  Automation would be possible, but I have not heard of it. Many interurbans used automatic substations to save manpower. On the Sacramento Northern (OA&E), about 60 miles in length prior to the merger, there were five main substations. The only maned station was at the drawbridge, where the drawbridge operator doubled as the substation operator. The remaining substations were automatic, turned on on low voltage and off on low current. There was a bit more to it than that, but that was the basic idea.  Automatic substations were in use by 1920.  

A light bulb would never be used to indicate that power was on.  If the lamp burned out it would produce a false indication that the line was safe when it was not. 

Catenary systems did not necessary up use larger wire than simple suspension systems, and many catenary systems were built on wooden poles with bracket arms, just like simple suspension.  Two reasons for catenary, supporting the contact wire every 15 feet, rather than every 100 feet at the poles, resulted in a flatter wire suitable for higher speed. The other reason is with poles every 150 feet, it used fewer poles.  All if the catenary systems I have worked on use a 4/0 contact wire. I have seen simple suspension systems use 2/0, 3/0 or 4/0 trolley wire.