Speed Limits and Opposing Train Movement

[rjemery]

Not true, it simply means that the signal can't give an indication that conflicts with a switch. At CP Potter the signal for the WB can't indicate Clear (Green) until the switch is lined so that he can go west. If the switch is lined for WB on Track 2 to go west, then a WB on Track 1 will always see a Stop (Red) Indication. That's all an Interlocking is, a Switch (or Bridge) interlocked to a signal. So a Drawbridge is also an Interlocking.

Beaulieu,

Since you know much more than I will ever know about train operations, I accept your explanation.  It is reasonable.

[rjemery]

Quick question, not remembering who got what in the Conrail split, is this CSX or NS track?

To the best of my knowledge, NS and CSX could not agree how to divy Conrail assets in the NJ-NY-PA metropolitan area as well as in the Detroit area.  They then formed a new corporation, Conrail Shared Assets Operations, of which NS owns 58 percent and CSX 42 percent.  In that fashion, Conrail lives on.  Other assets elsewhere of the old Conrail were transferred to either NS or CSX.

Thus, when we speak of Conrail today, most often we mean the new Conrail Shared Assets Operation.  And to answer your question, both NS and CSX own the ex-LV line where I do my trainwatching.

Conrail locomotives I have seen are painted in the dress blues scheme.  Along this ex-LV line, I see NS, CSX, Conrail and foreign flag locos in about equal numbers.  I have even seen a number of fallen flag locos traverse this stretch, MP being the most notable.  I have witnessed a number of BNSF locos in the new and the revived warbonnet paint scheme, and a goodly number of UP locomotives.

[beaulieu]

Potter is an interlocking and is so designated in the TT. Actually it's designated a Controlled Point, but six of one, half a dozen of the other.

A CP, as in a single point, I would understand.  An interlock, however, suggests at least two potentially conflicting parts. If there is an A, there needs to be at least a B. If Potter is the A, where is the B?  Therefore, I don't think Potter is a true interlock.

Not true, it simply means that the signal can't give an indication that conflicts with a switch. At CP Potter the signal for the WB can't indicate Clear (Green) until the switch is lined so that he can go west. If the switch is lined for WB on Track 2 to go west, then a WB on Track 1 will always see a Stop (Red) Indication. That's all an Interlocking is, a Switch (or Bridge) interlocked to a signal. So a Drawbridge is also an Interlocking. 

[n012944]

Quick question, not remembering who got what in the Conrail split, is this CSX or NS track?

 

Bert

[Anonymous]

I much appreciate this information and explainations, I enjoy learning new things about trains and why things are done the way they are.

[rjemery]

Potter is an interlocking and is so designated in the TT. Actually it's designated a Controlled Point, but six of one, half a dozen of the other.

A CP, as in a single point, I would understand.  An interlock, however, suggests at least two potentially conflicting parts. If there is an A, there needs to be at least a B. If Potter is the A, where is the B?  Therefore, I don't think Potter is a true interlock.

[zardoz]

and you say a engineer will stop his train after a air brake application with the slack bunched so as not to get a drawbar? I never knew this. I need to get here more often and learn these things. just how does this happen?

Better try it on Train Simulator first.

[nbrodar]

Potter is an interlocking and is so designated in the TT. Actually it's designated a Controlled Point, but six of one, half a dozen of the other.

Nick

[rjemery]

Interlocking ? I was under the impression it was a switch.

It is a single switch.  An interlock is generally thought of as "an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions, crossings, and so forth."  See http://en.wikipedia.org/wiki/Interlocking

Don't blame Beaulieu.  It's hard to picture the scene from a written account no matter how lengthy the description.  I wish I could attach a map or diagram so that the exact situation could be well understood by all.  Beaulieu probably just referred to Potter as an interlock because it is a choke point requiring dispatcher intervention. Maybe in the ETT it is listed as an interlock. 

[wabash1]

My understanding of signaling here is that the top signal is for the track dead ahead, while the bottom signal is for the diversion onto the siding.  If the e/b freight is going to be diverted onto the siding, then the top signal will always be red, while the bottom signal will be yellow (or flashing yellow).  The bottom signal would never be green because of speed restrictions going over a switch.  Red over red would mean a complete stop, but that signal post must be a permissive red, because I have seen trains advance slowly past the red over red.

RJ, I suspect that the Engineer of the first eastbound that you saw probably had a single yellow indication at the preceeding signal and had committed to stop at the interlocking with the switch.  If he had made a heavy brake application and gathered the slack in the train, the safest course for him was to let the train come to a complete stop before releasing the brakes. With the slack gathered and a heavy train it is very easy to break a coupling or worse pull a drawbar, by making a brake release without stopping. Based upon your information that the EB signal was Red over Yellow and changed to Red over Flashing Yellow, I think you just missed an EB ahead of the two that you saw.

Interlocking ? I was under the impression it was a switch. and you say a engineer will stop his train after a air brake application with the slack bunched so as not to get a drawbar? I never knew this. I need to get here more often and learn these things. just how does this happen?

[nbrodar]

The max speed for the Lehigh Line is 50 MPH.  But max speed is irrelevent for any signal other then Clear.

A high yellow means Approach...Proceed prepared to stop at the next signal, not exceeding Medium speed (30 MPH).

A high flashing yellow means Advance Approach...Proceed prepared to stop at the SECOND signal, not exceeding Limited Speed (40 MPH).

Red over flashing yellow means Medium Approach...Proceed prepared to stop at nedt signal, not exceeding Medium Speed.  Trains exceeding Medium Speed, must begin deduction to Medium Speed as soon as the Medium Approach signal is clearly visible. 

Red over yellow means Restricting...Proceed at Restricted Speed (a speed which will permit stopping with in one half the range of vision, short of train, on track equipment, misalinged switch or derail, or any other obstruction, not exceeding 15 MPH.

The first E/B came up to Potter with an Approach.   So the engineer came up ready to stop.  Arriving at Potter he saw the Restricting and decided to wait for a more favorable signal.  Because the first E/B was in the block ahead, the second E/B received a Restricting.  This engineer decided to take the Restricting and follow the train ahead.

The Restricting aspect can apply to either route. 

BTW: Potter is Absolute, you can pass a Red over Red, but only with permission of the Dispatcher.

Nick

[rjemery]

Red is most restrictive. I dont know if both the E/B or W/B train was on the SAME track facing each other but I would think that the e/b engine has to stop because his track is occupied.

The two trains were facing each other on the same track.  However, the e/b freight could have proceeded onto the secondary.  The switch was set for that diversion, and my understanding of the red over yellow signal permits the e/b train to move.

The signal you describe must be specific to that secondary track.

It is not.  As is typical in US railroading, the top signal is for the track ahead while the bottom signal is for the diversion, although other systems exist.  Had this been a single line main with no switch, a signal would typically have just one light.

Me wonders how long that poor W/B engine crew must have felt.

The first w/b sat there for at least 45 minutes.  That is not unusual for trains waiting for the single line main ahead to clear.

What I dont know is this: Is there a yard or something that is ahead of the W/B train waiting on the main? Whoops: Edit: I noticed you stated that the W/B train was cleared to go and there was ANOTHER W/B behind that.

There are no yards in the vicinity.  The nearest yard is Oak Island terminal in Newark, some twelve miles east of Potter.

My question is this: I recognize you call this a secondary track or a siding that both E/B's went into. In reality it's a double tracked main from that particular switch and signal we are discussing?

I am not that well versed in railroad terminology.  Potter is a choke point, where two tracks merge into one.  East of Potter, it is a dual-track main, and I think further east at Aldene, it becomes a three track main.  West of Potter, the track is a single line to Bound Brook, some 12 miles distant.

Here is another question. The west bounder sitting on the switch waiting on the EB'er, which side of the W/B's train did the E/B'er end up on as he went onto the Secondary track? Did the W/B train watch the E/B'er pass on his right or left side?

The w/b trains held at the switch were on the left-hand track as viewed from their cabs.  The secondary was on the right.  That, too, was unusual at Potter.  Most times, the w/b trains are on the secondary and merge onto the main.

Here is another question. The E/B engineer is confronted with a signal that is apparently one above the other. Which signal controls the main and which signal governs the secondary or siding track?

As noted above, the top signal governs the main while the bottom signal indicates the diversion.  Most times, e/b trains stay on the main and get a green or yellow over red at the signal I watch.

[Anonymous]

No one knows the answers to my questions then? I'll visit the library and see what I can learn.

[rjemery]

I agree with Spokyone that it sound like the E/B was waiting for a track warrant.

This is a fully automated block signal CTC stretch of track, so why use a track warrant?  If anything, the track warrant system, at least here, seems to have slowed things down and added to the congestion.

Starting at Potter, the railroad is laying a second track w/b, probably to at least Bound Brook.  When completed, I expect trains will move e/b and w/b without interfering with one another.  Also at Potter, new crossover switches are being installed.

[n012944]

I was thinking the first E/B was waiting for track warrant. Perhaps dispatcher wanted to wait until second W/B cleared the crossover 5 or 6 miles away. Waiting to see what MC or 1435mm say.

A likely possibility. I did see the headlight of the second w/b way in the distance, and it did appear to be on the second track at least initially. However, if it did cross onto the main and behind the first w/b, it should have completed that movement well ahead of the arrival of the first e/b.  Maybe the dispatcher took a coffee break!

Could have been a number of things.  I agree with Spokyone that it sound like the E/B was waiting for a track warrant, why it took so long, that I do not know.  The second w/b might have had switch problems and did not give back his block until it was fixed.  The dispatcher also could have been accupied with something else and could not give a track warrent right away.  Remember that Class 1 dispatchers, on average, dispatch over 300 miles of track, and the dispatcher could have taking care of something more important.

[rjemery]

... Based upon your information that the EB signal was Red over Yellow and changed to Red over Flashing Yellow, I think you just missed an EB ahead of the two that you saw.

Judging from the sound of air horns, there was rail traffic in the area before I arrived at Potter, but I don't think I just missed an e/b prior to arriving at the site.  There was no train disappearing into the distance on the secondary, and the e/b signal was dark.  That signal only became illuminiated when an e/b freight enters the block some 10 or miles to the west.  I also believe the dark signal meant there was no train in the block ahead on the second track.

When the signal became illuminated (red over yellow), I then knew an e/b was approaching.  When it finally did come into sight, I was surprised that it stopped.  In past situations, given a red over yellow signal and a train dead ahead on the main, the e/b train just eases onto the siding and continues on its way.  This was the first time I saw a train in this situation come to a dead stop.  That was both unique and puzzling to me.

[rjemery]

I was thinking the first E/B was waiting for track warrant. Perhaps dispatcher wanted to wait until second W/B cleared the crossover 5 or 6 miles away. Waiting to see what MC or 1435mm say.

A likely possibility. I did see the headlight of the second w/b way in the distance, and it did appear to be on the second track at least initially. However, if it did cross onto the main and behind the first w/b, it should have completed that movement well ahead of the arrival of the first e/b.  Maybe the dispatcher took a coffee break!

This area also has one other complication for engineers -- grade crossings.  If the trains stop, they have to position themselves behind any trip for crossing gates.  There are three grade crossings within a two mile stretch that includes Potter (at Inman Avenue, Edison).  The other two grade crossings are Tingley Lane, Edison, and Rahway Avenue, Westfield. The trains are generally short enough that they do not block a crossing, but that situation has occurred.  Those crossings are very busy roads.

 

[beaulieu]

My understanding of signaling here is that the top signal is for the track dead ahead, while the bottom signal is for the diversion onto the siding.  If the e/b freight is going to be diverted onto the siding, then the top signal will always be red, while the bottom signal will be yellow (or flashing yellow).  The bottom signal would never be green because of speed restrictions going over a switch.  Red over red would mean a complete stop, but that signal post must be a permissive red, because I have seen trains advance slowly past the red over red.

RJ, I suspect that the Engineer of the first eastbound that you saw probably had a single yellow indication at the preceeding signal and had committed to stop at the interlocking with the switch.  If he had made a heavy brake application and gathered the slack in the train, the safest course for him was to let the train come to a complete stop before releasing the brakes. With the slack gathered and a heavy train it is very easy to break a coupling or worse pull a drawbar, by making a brake release without stopping. Based upon your information that the EB signal was Red over Yellow and changed to Red over Flashing Yellow, I think you just missed an EB ahead of the two that you saw.

[spokyone]

rj What a great day you had. I was thinking the first E/B was waiting for track warrant. Perhaps dispatcher wanted to wait until second W/B cleared the crossover 5 or 6 miles away. Waiting to see what MC or 1435mm say.

[rjemery]

My understanding of signaling here is that the top signal is for the track dead ahead, while the bottom signal is for the diversion onto the siding.  If the e/b freight is going to be diverted onto the siding, then the top signal will always be red, while the bottom signal will be yellow (or flashing yellow).  The bottom signal would never be green because of speed restrictions going over a switch.  Red over red would mean a complete stop, but that signal post must be a permissive red, because I have seen trains advance slowly past the red over red.

[Anonymous]

Red is most restrictive. I dont know if both the E/B or W/B train was on the SAME track facing each other but I would think that the e/b engine has to stop because his track is occupied. When the signal became a flashing yellow I think it was permissive for the e/b to go into the siding at a restricted speed ready to stop short of any problems. The signal you describe must be specific to that secondary track.

If I saw yellow anything, my speed should be below 40 on a 60 mph track. I could be wrong and welcome a correction.

The second e/b was given a red over red because that signal gaurds the secondary track which is currently being used by the first E/B. I think when the signal became red/yellow for the secondary track, that means the first e/b train has cleared that secondary track (Assumed to have finished passing the poor W/B stuck in the hole) and now the second E/B knows he needs to get into that secondary track.

Me wonders how long that poor W/B engine crew must have felt. What I dont know is this: Is there a yard or something that is ahead of the W/B train waiting on the main? Whoops:

Edit: I noticed you stated that the W/B train was cleared to go and there was ANOTHER W/B behind that.

My question is this: I recognize you call this a secondary track or a siding that both E/B's went into. In reality it's a double tracked main from that particular switch and signal we are discussing?

Here is another question. The west bounder sitting on the switch waiting on the EB'er, which side of the W/B's train did the E/B'er end up on as he went onto the Secondary track? Did the W/B train watch the E/B'er pass on his right or left side?

Here is another question. The E/B engineer is confronted with a signal that is apparently one above the other. Which signal controls the main and which signal governs the secondary or siding track?

[rjemery]

On a Conrail straightaway in NJ near me [Potter (Edison, NJ), ex-LV], where I believe the top speed could well be at least 60 mph if not 79 mph, what would be a typical speed for a yellow and flashing yellow aspect?

I witnessed this situation yesterday:  At Potter, two w/b tracks come together to make a single main.  A w/b freight on the main track was being held before the switch.  The secondary track was clear as far as the eye could see (about four miles).

The e/b signal was showing red over yellow. A second freight approached the e/b signal and came to a complete stop.  There were now two freights facing each other on the same track, both at a dead stop, with a switch in between.

The switch ahead was set for the e/b freight to divert onto the siding.  Not until the e/b signal changed to red over flashing yellow did the e/b freight advance and move onto the siding and clear the block.

I never witnessed such a movement before.  Why did the e/b freight stop when it had a yellow diversion signal, the points were set properly and the siding clear as far as the eye could see?

There is more.  Another e/b freight approached even before the first completely moved onto the siding.  It waited until the e/b signal changed from red over red to red over yellow -- not a flashing yellow.  It then moved onto the siding as well.

Not surprisingly, as soon as this second freight cleared the switch, the points were reset for the w/b freight to proceed.  There was actually another w/b freight behind the first w/b, for a total of four movements in about 30 minutes. Great trainwatching.