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Control of interlockings

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Control of interlockings
Posted by Lithonia Operator on Thursday, December 2, 2021 9:04 AM

Are most U.S. interlockings now controlled by far-remote dispatching centers? Are are there still a significant numbers of towers in use?

I was thinking about, say, Rochelle. How do UP and BNSF coordinate the movements there? On my one quick visit there I saw no tower. Do far-away BNSF and UP dispatchers run things, but have some type of hotline between them?

Or do the railroads perhaps alternate who controls that diamond, taking, say, monthly turns?

In the old days, did affected railroads alternate staffing the towers at multi-railroad interlockings?

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Posted by DSchmitt on Thursday, December 2, 2021 10:09 AM

  

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Posted by BaltACD on Thursday, December 2, 2021 10:33 AM

There are nominal three ways railroad crossings at grade are handled in the 21st Century besides having a on site Tower providing direct control.

Automatic - circuits are arranged to provide signals to trains on a first come, first served basis.

Dispatcher Control - One carrier or the other's Train Dispatcher has direct control of the signals at the crossing and lines them as necessary.

In some cases the signals controlling the crossing may be 'hold out' signals for some other operation that takes place beyond the crossing - The crossing itself can be fully automatic for who actually gets the signal, with that being said the Dispatcher can 'hold' the crossing signal - thus not announcing the train to the signal logic of the crossing itself.  

Back in the day - there were a number of railroad crossing at grade that were not interlocked in any way.  One location was the Center Street Crossing just East of Youngstown, OH.  Those involved in the crossing were B&O, PRR, P&LE & ERIE.  The crossing was controlled by a person designated as Train Director that moved trains via colored hand signals for each railroad involved.  Each carrier had Statutory Stops defined in their TTSI on both sides of the crossing.  Getting a manual 'highball' of the right color (flags by day, lights by night) from the Train Director was the proper signal to proceed.  As I recall the Train Director position was protected off the Brakeman's extra list of each carrier on a rotating quarterly basis.

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Posted by Lithonia Operator on Thursday, December 2, 2021 11:11 AM

Thanks, Balt.

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Posted by n012944 on Thursday, December 2, 2021 11:17 AM

Rochelle is an automatic crossing.

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Posted by CSSHEGEWISCH on Thursday, December 2, 2021 12:02 PM

Brighton Park was one of the last, if not the last, non-interlocked crossings in the Chicago area.  Trains made a statutory stop and were cleared by semaphore indication.  The Special Instructions in IC's ETT used to show a gap in CTC at Brighton Park.

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Posted by timz on Thursday, December 2, 2021 12:11 PM

Lithonia Operator
In the old days, did affected railroads alternate staffing the towers at multi-railroad interlockings?

Wasn't the later arrival usually responsible for the cost of the interlocking operator?

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Posted by tree68 on Thursday, December 2, 2021 12:11 PM

Deshler is controlled from JAX - I forget which desks.  Both lines are CSX, so that's not an issue.  IIRC, the diamond is under control of one of the desks, but the rest of the Toledo Sub, and the tracks east and west of Deshler are under three different desks.

The tower at Deshler is now MOW, having been closed as a control facility years ago.

The tower at Fostoria (FC) was closed just recently.  I believe it covered both CSX and NS, but I don't know how that arrangement works.

I recall reading in the past that sometimes the day shift for joint facilities would be covered by railroad A, with the swing shift covered by railroad B, or arrangements along that line.

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Posted by Lithonia Operator on Thursday, December 2, 2021 12:34 PM

I had originally written Deschler when I meant to write Rochelle. Changed it above.

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Posted by SD70Dude on Thursday, December 2, 2021 12:50 PM

Some surprisingly busy interlockings are still automatic, and operate in a surprisingly primitive manner.  

I'll use CN and CP on the east side of Edmonton as an example.  Our mainline crosses a CP branchline at the east end of our Clover Bar yard, and there are crossings everywhere.  Our RTC will set up meets on a short stretch of double track here and crews will try to time it so neither train has to stop, but then CP will show up and dial in the interlocking just before us (it's a two way street, we can do it to them too), leaving us stopped on crossings and looking at a red light and the side of a CP train.

The same CP line crosses a CN branchline a few miles to the southwest.  In a recent conversation with an RTC we realized that it would be possible for long trains of both railways to block each other at the two interlockings while holding back clear of crossings or waiting for a meet, and no one could move on their own without having to cut crossings.  

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Posted by BaltACD on Thursday, December 2, 2021 1:08 PM

Lithonia Operator
I had originally written Deschler when I meant to write Rochelle. Changed it above.

And when talking about Deshler - drop the c

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Posted by jeffhergert on Thursday, December 2, 2021 9:05 PM

UP controls the manual interlocking at Fremont NE where BNSF crosses the UP.  Approaching BNSF trains call up the UP dispatcher for a signal to cross.  It used to be on the UP road channel, but I haven't heard them for a long time.  I'm guessing the UP dispatcher can now answer the BNSF trains on their radio channel.

The UP dispatcher would tell the BN guys to either come on down and look for a signal or hold back because a UP train was already lined through.  The best one I heard, before the BN guys went silent, was a BN calling for a signal.  The UP had a MOW curfew on the diamond for some major work on it.  The UP dispatcher said it would be about 6 hours before they got a signal.  Oops!  Someone didn't get the memo.

There's also a few manual/automatic interlockings.  It's where there is a railroad crossing that's an automatic interlocking, but also a manual interlocked switch controlled by the dispatcher.  An unintended Stop signal may mean both operating the automatic's release box and getting authority from the dispatcher if the signal doesn't clear after operating the release.

Jeff

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