The preceding is for typical freight or freight and passenger situations. 12 miles seperation can give you a train every five minutes for very short trains if speeds of all are the same at 60mph. If the trains were long, still at 60 mph, then 6 minutes would be the minimium spacing.
With closer signal spacing and more than three aspects, as in the PRR and LIRR Hudson and East River tunnels and between Mott Haven and Grand Central Terminal, every two minutes. At some pointes on New York City's subway system, every 100 seconds, with improvement to every 90 seconds considered a possibility. My understanding is that the Chicago Loop had even closer headways, perhaps it still does.
steve-in-kvilleHow far apart, time wise, must each train be on a mainline? Just from my observation, it seems right around 20 minutes or so. This is provided a train doesn't need to stop and service a customer.
The time honored answer is - It depends.
At Restricted Speed at a nominal 15 MPH, it will take a nominal 1 mile long train 4 minutes of more to pass a point. With signal failure and/or other operating situations it is POSSIBLE (though unlikely) for a second train to be following with the EOT of the lead train being in visual sight. Restricted Speed also contains the caviet - being able to STOP WITHIN ONE HALF THE RANGE OF VISION.
On Main Line signalled tracks - what is the signal spacing that the carrier has for the line being observed. Sometimes, on some carriers, signals might be spaced less than a mile apart. Through the 70's, 80's and 90's most carriers had signal spacing set at nominally 2 miles. Entering the 21st Century, with the larger trains being operated the spacing has been increased to 3 miles or more.
The normal progression of signals BEHIND a train will be; Signal immediately behind the train Restricted Proceed; 2nd Signal beind the train Approach; 3rd Signal behind the train could be Clear or Advance Approach; 4th Signal will be Clear, even if the carrier uses the Advanced Approach indication in their signaling system. If we are expecting the following train to be operating on a Clear signal, and we have spacing of 3 miles between signals, then the following train can get a Clear indication no closer than 9 miles behind the lead train and potentially 12 miles. Approach Indication's require trains exceeding Medium Speed or 30 MPH (rule books vary) to immediately reduce to that speed and approach the next signal Prepared to Stop.
Never too old to have a happy childhood!
To this we might add the time effect of the train speeds.
There are a number of accounts from the days the NYC operated crack trains in 'sections' and closest spacing at 85mph was an advantage, of sitting on the open platform and seeing the headlight of the following train... in one account, being close enough to make out the plume of steam from the feedwater heater.
You could see this in the '70s on the ex-IND subway below 145th where when riding an A downtown you could clearly make out the D on a following train when moving at top speed.
OvermodTo this we might add the time effect of the train speeds. There are a number of accounts from the days the NYC operated crack trains in 'sections' and closest spacing at 85mph was an advantage, of sitting on the open platform and seeing the headlight of the following train... in one account, being close enough to make out the plume of steam from the feedwater heater. You could see this in the '70s on the ex-IND subway below 145th where when riding an A downtown you could clearly make out the D on a following train when moving at top speed.
And when the lead train stops -
In the day - a high number of the accidents were rear end collisions account the following train(s) exceeding the speeds of the signal indication, expecting the signal to change to a more favorable indication before they passed it.
BaltACD steve-in-kville How far apart, time wise, must each train be on a mainline? Just from my observation, it seems right around 20 minutes or so. This is provided a train doesn't need to stop and service a customer. The time honored answer is - It depends. At Restricted Speed at a nominal 15 MPH, it will take a nominal 1 mile long train 4 minutes of more to pass a point. With signal failure and/or other operating situations it is POSSIBLE (though unlikely) for a second train to be following with the EOT of the lead train being in visual sight. Restricted Speed also contains the caviet - being able to STOP WITHIN ONE HALF THE RANGE OF VISION. On Main Line signalled tracks - what is the signal spacing that the carrier has for the line being observed. Sometimes, on some carriers, signals might be spaced less than a mile apart. Through the 70's, 80's and 90's most carriers had signal spacing set at nominally 2 miles. Entering the 21st Century, with the larger trains being operated the spacing has been increased to 3 miles or more. The normal progression of signals BEHIND a train will be; Signal immediately behind the train Restricted Proceed; 2nd Signal beind the train Approach; 3rd Signal behind the train could be Clear or Advance Approach; 4th Signal will be Clear, even if the carrier uses the Advanced Approach indication in their signaling system. If we are expecting the following train to be operating on a Clear signal, and we have spacing of 3 miles between signals, then the following train can get a Clear indication no closer than 9 miles behind the lead train and potentially 12 miles. Approach Indication's require trains exceeding Medium Speed or 30 MPH (rule books vary) to immediately reduce to that speed and approach the next signal Prepared to Stop.
steve-in-kville How far apart, time wise, must each train be on a mainline? Just from my observation, it seems right around 20 minutes or so. This is provided a train doesn't need to stop and service a customer.
When UP started placing waysides on the exCNW double track, and upgrading from plain ABS to CTC on other single track lines, they've seem to shortened block lengths. 1.25 to 1.5 mile blocks in many places, with some longer ones in places.
Many of the blocks they replaced were in the 2 to 3 mile length. UP uses the Advance Approach (Red, Yellow, Flashing Yellow, and Green signals) and the older ABS systems that were replaced didn't. In many places the distance from the Green to the Red signal hasn't changed too much with the shorter blocks, they just added a another signal block within that distance.
Jeff
Regards - Steve
steve-in-kvilleHeard over the radio this past weekend.... 13,000' train had to be stopped (don't know why). If its illegal to block a crossing for more than 20 minutes, why run a train that long that can't find a place to stop without blocking a crossing? I heard a dispatcher tell a crew to "just stop where you can. You're just gonna have to block a crossing."
Ideally, you're never going to face that situation, but we all know that it's going to happen. Railroads generally run the risk of being fined for blocking the crossing, but that's only going to happen if the appropriate authorities are aware of the blocking.
In a city, that won't take long. If it's a lonely country crossing, hardly anyone will notice.
That's why many yards will have "hold out" locations where a train can wait without blocking any crossings if they can't get into the yard right away.
I'm not sure, but it's possible that laws against blocking crossings for excessive periods may only apply to standing trains. If that two and a half mile long train takes a half hour to creep over a crossing...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
steve-in-kvilleI remember the crew and the dispatcher were debating what block to stop on, and perhaps they were debating which crossing to block would be the best. For all I know, they only sat for a few minutes before they were rolling again.
From CSX's Baltimore Division Timetable for trains going to Richmond.
312 HIGHWAY-RAIL CROSSINGS AT GRADE - SIGNAL INFORMATION
Southward train crews must contact the BD Dispatcher prior to passing Vaughn Rd, CFP 15.62 if their train is longer than 6,600 feet.
Southward train crews observing a signal, or series of signals, less than clear, between Vaughn Rd, CFP 15.62 and Greendale, CFP 4.8, must apply the Rule 312 information inmust the chart below prior to passing the associated location. When necessary, consult with the BD Dispatcher to avoid blocking or fouling Highway-Rail Crossings. The below chart has built in the minimum allowance for Rule 312.1 compliance.
MP Location Feet Instruction
CFP 13.85 Ashcake Rd 4080 SouthwardCFP 12.95 Gwathmey Church Rd 6640 SouthwardCFP 11.55 Elmont Rd 0 SouthwardCFP 11.15 Cedar Ln 7187 SouthwardCFP 9.65 Mill Rd 7126 SouthwardCFP 8.10 Mountain Rd 7512 SouthwardCFP 6.60 Hungary Rd 5340 SouthwardCFP 5.45 Hermitage Rd 1462 Southward
I've seen similar entries in the IHB ETT regarding the holding out of trains over a certain length east of Cottage Grove Ave if they don't have immediate clearance into Blue Island yard from the east.
While we have places we can't stop because of bothering adjacent residents, especially those with some clout, they don't care as much anymore about blocking crossings. (At least those crossings in rural areas.) Here's why.
https://about.bgov.com/news/rail-prevails-as-long-trains-block-first-responders-at-crossings/
There's still a few crossings, again those used by people with some clout, that we're not to block.
While the railroad may not care as much anymore, most of us in the field still do. We try to not block the important crossings.
That article says, in effect, that an intermodal car is about 9 times the length of a hopper. That's not even close to true, is it? More like triple, maybe?
Lithonia OperatorThat article says, in effect, that an intermodal car is about 9 times the length of a hopper. That's not even close to true, is it? More like triple, maybe?
As I recall - the 5-pack intermodal cars are nominally 300 feet in length.
5 60 foot drawbar linked carbodies that can handle 53 foot and all smaller containers.
While some may think of this as 5 cars; there is a single car number applied to it and each 'pedestal' is lettered as a part of the car. If one mechanical element on any of the individual pedestals develops a serious problem that requires set out - the car (all 5 drawbar equipped pedestals) to be set out and the track must be able to hold a 300 foot car.
Where I live, I hardly ever see trains, to be honest. The Maine Central Mountain Division, at its nearest point, is about ten miles away, but there hasn't been a train there in over 20 years. I have to drive about 20 miles to get to an active line, and almost all lines in Maine are very low-density.
Mainly, I see trains when we're traveling, and that's pretty hit-or-miss; like maybe the middle of a train on an overpass. Occasionally I actually do some focused train-watching, like an hour and a half in Folkston GA a few years ago. More often, I am just following tracks while simultaneously trying to get somewhere.
So I'm not sure I've ever even seen the type of container flats you mentioned. I've no doubt seen pix of them many times, but never realized that was "one car." Is one as likely to see such cars on the east coast as out west?
The writer of that article said a 150-car intermodal train could be over 33,000 feet. But no one runs 6-mile-long trains (!!), do they? That would call for some serious distributed power. And could fit in virtually no sidings.
Lithonia OperatorSo I'm not sure I've ever even seen the type of container flats you mentioned.
Surely you've seen articulated sets of well cars. They are common in three-unit sets as well as five-unit sets (and you can tell from a distance what they are by the distinctive rhythm patterns of the wheel arrangement), There are also sets of more conventional underframes (not depressed wells for stack service) that are articulated.
There are of course several designs of well car, some of which look superficially similar. We've had threads here that discuss the numbering of the 'units' making up these cars, and how the individual trucks and wheels are numbered for service identification.
Overmod (and you can tell from a distance what they are by the distinctive rhythm patterns of the wheel arrangement),
Whilst camping at Deshler, I can lay in my tent and tell whether they are single cars, three, or five sections by the rhythm of the wheels over the diamond.
Lithonia OperatorWhere I live, I hardly ever see trains, to be honest. The Maine Central Mountain Division, at its nearest point, is about ten miles away, but there hasn't been a train there in over 20 years. I have to drive about 20 miles to get to an active line, and almost all lines in Maine are very low-density. Mainly, I see trains when we're traveling, and that's pretty hit-or-miss; like maybe the middle of a train on an overpass. Occasionally I actually do some focused train-watching, like an hour and a half in Folkston GA a few years ago. More often, I am just following tracks while simultaneously trying to get somewhere. So I'm not sure I've ever even seen the type of container flats you mentioned. I've no doubt seen pix of them many times, but never realized that was "one car." Is one as likely to see such cars on the east coast as out west? The writer of that article said a 150-car intermodal train could be over 33,000 feet. But no one runs 6-mile-long trains (!!), do they? That would call for some serious distributed power. And could fit in virtually no sidings.
Suggest the Horseshoe Curve Webcam. NS operates just about every kind of equipment past the camera .
https://www.youtube.com/watch?v=r66gM9eLPuA
Video of a 18K foot UP stack train with multiple DPU's from 2010
https://www.youtube.com/watch?v=JYdId4rtaeQ
Lithonia OperatorSo I'm not sure I've ever even seen the type of container flats you mentioned. I've no doubt seen pix of them many times, but never realized that was "one car." Is one as likely to see such cars on the east coast as out west?
In addition to Balt's suggestion of HSC, may I recommend the YouTube feed from Deshler, OH, which is free. About six miles east of Deshler is the North West Ohio intermodal facility at North Baltimore. Any and all types of intermodal can be seen on the Deshler cam. Several of CSX's hottest intermodals pass though Deshler daily.
There's also the Trains' Rochelle webcam. When it's working.
I believe BNSF somewhat regularly runs 18K foot intermodals. 18K is UP's longest allowable length for intermodal, with 6K feet between DP consists. Other than the test trains I haven't heard of any that big. 14 or 15K is the biggest I've seen.
steve-in-kvilleDo the power lines along the tracks serve a purpose anymore? Isn't everything buried now?
Lines along railroad rights of way at one time served many purposes. Communication, Power Distribution and Signal controls. At one time virtually ALL company communication was conducted on company owned and operated pole line. As years went by, some pole lines had their maintenance performed by Western Union technicians rather than railroad employees - one of the first instances of 'outsourcing'.
In the late 50's & early 60's carriers started switching to microwave communications for their long distance communication needs. In the years since, the carriers have adopted the latest technologies as they have become sufficiently reliable.
The new signal installations that were caused by the implementation of PTC have been relying on coded satellite communication and other forms of wireless communication. On exception that I have noted is that at siding locations, one end of the siding has the satellite equipment and the other end is operated on a wire connection to the satellite equipment on the other end.
During my final working years, wire thefts were common from the existing pole lines - it would generally get discovered when those wires were actually in use, as whatever they were being used for would stop working. The wire being stolen was solid copper wire, that was favored when the wires were originally installed. Company police had some success in catching the perpetrators.
Do you mean the code lines?
At one time, that's how the signals talked to each other, and the poles also carried telegraph, telephone, and probably teletype.
Never mind buried, a lot of the signal information is now carried by radio or satellite. Most telephone and other communications (data, fax) will be found on commercial carriers.
Those poles also carried power in some cases, as I believe was discussed briefly here recently (or maybe on another thread).
If the pole line is still up and has wire on it, I might suspect it is still being used for communications between signals. I'm sure it will soon be replaced by other modes, if it hasn't already.
I'm sure others can shed more (and probably better) light on your question.
There are also places, although personally I don't think there were very many, where power lines (non-railroad-power-specific electricity) would share pole ROW with code or other lines. I believe parts of the Atglen & Susquehanna catenary support structure still stand because their HV lines 'on top' still supply 25Hz industrial customers.
About pole lines. See my post about them on signaling thread.
steve-in-kville But I recently read that the warmer and more humid air carries the furthest. So which is it?
I always thought it was cold air, too, so I looked it up. What I found was that warm air carries sound the fastest, but cold air carries it furthest. The warm air supposedly has to do with the air already being excited. The cold air would have to do with the density of the air.
Wind can be a significant factor, and can have two effects. First, and most obvious, is speed and direction. If you're upwind of the sound source, you won't hear it as far.
The second is ambient noise. We don't often think about it, but wind is noisy. If it's breezy, the noise of the wind in trees and around buildings can cover the sound of the trains.
What does REDI stand for?
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