Paul_D_North_Jr Chris30 I don't see JB Tower in W. Chicago becoming an automated crossing any time soon. The operations there are just too complex. Multiple grade crossings next to the diamond / tower make it more interesting. Even though the "J" operated the tower, the UP dispatcher (#11) dictated most of the movements through there because there were only a handful of "J" freights and trackage rights trains. Now, with CN taking over and wanting to run up to thirty trains a day through W. Chicago I expect some issues in the near future. I'm not sure if it can be done but the UP and CN might want to work out some type of joint operation with employees from both railroads working the tower on different shifts. It would make sense to have a UP employee operate the tower on the first and second shifts due to the Metra traffic and a CN employee cover the third shift because I expect a majority of the CN freight will move at night. CC There's an extensive discussion of this situation in the STB's Preliminary Environmental Assessment (? on exact title) for the CN/ EJ&E acquisition, including nearby "staging" (waiting) areas & lengths, hours of occupying the crossing, CN at night, etc. It's in/ under STB Finance Docket FD-35087, if I remember correctly, and in Sections 3.something (3.02 ?) for existing operations and Section 4.something (4.03 ?) for proposed operations, plus the Appendices. If I can find it again I'll post the links and citations to the specific pages. You fellas from Chi-town will likely find it very interesting. - Paul North.
Chris30 I don't see JB Tower in W. Chicago becoming an automated crossing any time soon. The operations there are just too complex. Multiple grade crossings next to the diamond / tower make it more interesting. Even though the "J" operated the tower, the UP dispatcher (#11) dictated most of the movements through there because there were only a handful of "J" freights and trackage rights trains. Now, with CN taking over and wanting to run up to thirty trains a day through W. Chicago I expect some issues in the near future. I'm not sure if it can be done but the UP and CN might want to work out some type of joint operation with employees from both railroads working the tower on different shifts. It would make sense to have a UP employee operate the tower on the first and second shifts due to the Metra traffic and a CN employee cover the third shift because I expect a majority of the CN freight will move at night. CC
I'm not sure if it can be done but the UP and CN might want to work out some type of joint operation with employees from both railroads working the tower on different shifts. It would make sense to have a UP employee operate the tower on the first and second shifts due to the Metra traffic and a CN employee cover the third shift because I expect a majority of the CN freight will move at night.
CC
There's an extensive discussion of this situation in the STB's Preliminary Environmental Assessment (? on exact title) for the CN/ EJ&E acquisition, including nearby "staging" (waiting) areas & lengths, hours of occupying the crossing, CN at night, etc. It's in/ under STB Finance Docket FD-35087, if I remember correctly, and in Sections 3.something (3.02 ?) for existing operations and Section 4.something (4.03 ?) for proposed operations, plus the Appendices. If I can find it again I'll post the links and citations to the specific pages. You fellas from Chi-town will likely find it very interesting.
- Paul North.
OK, here are the links and references:
STB's "Background and Overview" page: http://www.stbfinancedocket35087.com/html/bkgrndoverview.html
What is essentially the Internet or "html" format "Table of Contents" for the Draft EIS is:
at: http://www.stb.dot.gov/Decisions/readingroom.nsf/WEBUNID/61898F9CADC3C7508525748E006688AC?OpenDocument
The formal Table of Contents is at (23 pages, approx. 76 KB in size):
http://www.stb.dot.gov/Decisions/readingroom.nsf/UNID/61898F9CADC3C7508525748E006688AC/$file/00.07_TOC_July08.pdf
Chapter 3 - Affected Environment, Section 3.1 - Current Rail Operations - 03.01_RailOperations_July08.pdf - is at (34 pages, approx. 3,714 KB in size):
http://www.stb.dot.gov/Decisions/readingroom.nsf/UNID/61898F9CADC3C7508525748E006688AC/$file/03.01_RailOperations_July08.pdf
Almost the whole document is worth reading, despite its size (a lot of graphic figures that use up a lot of KB, I suspect). Sections 3.1.2.6 - Interlockings and 3.1.2.7. - Trains Staging Locations near Interlockings are on pages 3.1-7 through 3.1-16 (Pages 7 through 16 of 34 of the PDF version); Metra Operations over EJ&E at-grade crossings are discussed on pages 3.1-25 through 3.1-27 (Pages 25 through 27 of 34 of the PDF version). West Chicago - in addition to appearing in the various tables in this presentation - is depicted in Figure 3.1-4 - West Chicago Train Staging Locations on page 3.1-13 (Page 13 of 27 of the PDF version).
The description and analysis of the proposed rail operations are in Chapter 4 - Environmental Consequences, Section 4.1 - Rail Operations - 04.01_RailOperations_July08.pdf - is at (52 pages, approx. 453 KB in size):
http://www.stb.dot.gov/Decisions/readingroom.nsf/UNID/61898F9CADC3C7508525748E006688AC/$file/04.01_RailOperations_July08.pdf
While West Chicago appears at numerous places in this section, it (and Barrington) are principally discussed in Section 4.1.7.3 Proposed Action under the caption "Existing and Expanded Metra Service on Rail Lines That Cross Affected EJ&E" on pages 4.1-42 throught 4.1-45 (Pages 42 through 45 of 52 of the PDF version) and the accompanying associated tables and figures.
Also, note that Figure 4.1-5 - Historic Rail Traffic Patterns in Chicago, Sheets 1 and 2 of 2 on pages 4.1-18 and 4.1-19 (Pages 18 and 19 of 52 of the "PDF" version) are "Reprinted With Permission" from Trains ! (looks like Copyright 2004).
I did not see anything in either Appendix B - Rail Operations Analysis 02.00_AppendixB_July08.pdf (5 pages, approx. 52 KB in size) at: http://www.stb.dot.gov/Decisions/readingroom.nsf/UNID/61898F9CADC3C7508525748E006688AC/$file/02.00_AppendixB_July08.pdf or Attachment B1 - Applicants’ Projected Rail Traffic (CN’s March 12 and January 3, 2008 Letters) 02.01_AppendixB_Attachments_July08.pdf (75 pages, approx. 3.8 MB in size) at: http://www.stb.dot.gov/Decisions/readingroom.nsf/UNID/61898F9CADC3C7508525748E006688AC/$file/02.01_AppendixB_Attachments_July08.pdf that directly affected West Chicago, although there sure is a lot of interesting reading and data in there as well !
I hope this is informative. Let me know if you find anything else pertaining to this suject, either on the STB's website or elsewhere.
OK. But strictly speaking, if a tower is closed, all switches aligned and signals cleared, and is used as a schedule point or block station, it is "under control" of the dispatcher whether or not he can manipulate switches or signals.
RIDEWITHMEHENRY is the name for our almost monthly day of riding trains and transit in either the NYCity or Philadelphia areas including all commuter lines, Amtrak, subways, light rail and trolleys, bus and ferries when warranted. No fees, just let us know you want to join the ride and pay your fares. Ask to be on our email list or find us on FB as RIDEWITHMEHENRY (all caps) to get descriptions of each outing.
MP173RWM:Economically or operationally would it make sense for Fostoria Tower to remain open? Is that a special situation in the world of railroad operations? F Tower more of less is a traffic cop, actually acting as a subdivision within the CSX Great Lakes Division, Western Region. From time to time, particularly in the winter months while landlocked inside, I will listen to the scanner feed at Fostoria and it is quite a location (never been there). The flow of trains not only thru town, but also from line to line is rather fluid. Could that be accomplished as well or better from a centralized location?BTW....thanks for the suggestion on Vance...I am about 65 pages in and it is very, very educational. What a great perspective to write a book, the geographically history. Not only is this a book on railroading, but also a historical economics lesson. ed
RWM:Economically or operationally would it make sense for Fostoria Tower to remain open? Is that a special situation in the world of railroad operations?
F Tower more of less is a traffic cop, actually acting as a subdivision within the CSX Great Lakes Division, Western Region.
From time to time, particularly in the winter months while landlocked inside, I will listen to the scanner feed at Fostoria and it is quite a location (never been there). The flow of trains not only thru town, but also from line to line is rather fluid. Could that be accomplished as well or better from a centralized location?BTW....thanks for the suggestion on Vance...I am about 65 pages in and it is very, very educational. What a great perspective to write a book, the geographically history. Not only is this a book on railroading, but also a historical economics lesson.
ed
Ed -- I'm shan't comment on what railways should do or will do.
Glad you're finding Vance useful. For me it put order, rigor, and science, for what for me had been a lot of chaotic observation, thought, and unfinished threads. Given what I've seen on this forum of your inquisitive and open mind, I thought it would be as useful for you as it was for me ...
RWM
henry6 BaltACD To my knowledge, no tower or control point was ever 'shared' between Train Dispatcher control and operator control. Define "control". A tower could be "closed", no operator on duty, but still be a block station or block limit station under the "control" of the dispatcher. The dispatcher may not operate any of the switches or signals at the location but can use the location to base train orders and schedules.
BaltACD To my knowledge, no tower or control point was ever 'shared' between Train Dispatcher control and operator control.
Define "control". A tower could be "closed", no operator on duty, but still be a block station or block limit station under the "control" of the dispatcher. The dispatcher may not operate any of the switches or signals at the location but can use the location to base train orders and schedules.
Never too old to have a happy childhood!
Since I worked only in Illinois, I don't know about other states. But along the route of the old C&A - later GM&O, ICG, CMW, SP and now UP - the road that was there first signed the pay checks of the tower employees. Thus Iles (Springfield) had 'Wabash' employees, Joliet had CRIP employees, but Corwith had C&A lineage employees.
I worked at Corwith and would not let ATSF freight trains, leaving or entering the yard, hinder the passage of our trains - much to the chagrin of the Corwith Yard Master, an ATSF employee; but I was within my rights if you go by the rule book of that time.
Now who actually is footing the bill for the tower and employees is determined by the original contract signed by the original two roads.
Art
As I said there are now interlockings on New Jersey Transit for instance that I would never have imagines could be remote controlled. Some of it is becaus of the simplification of the interlockings and schedules, Yes. But still in a terminal location like Dover, there are several moves going on at the same time, some crossing over in front of or behind other trains, etc. in short spans of time (less than 5 minutes say) that have to take concentration away from other interlocking locations and attending moves. And take into consideratin the dispatcher has to set up his moves at Dover based on what has been or has to be set up at Denville to the east and Port Morris/Landing/Lake Hopactcong to the west. It is truly amazing what is accompolished by so few, yet so effeciently and yets safely, today!
blue streak 1 Anyone:: Isn't there a few towers around the country that are manned during times of local high useage (ex. constant switching moves across diamonds, etc) and then remote dispatcher controlled at other times?
Anyone:: Isn't there a few towers around the country that are manned during times of local high useage (ex. constant switching moves across diamonds, etc) and then remote dispatcher controlled at other times?
The only real 'problem' with this operation is that when signal conditions caused the Home Signal at the tower displayed at STOP indication, because the signal did not have a number board trains had to obtain verbal permission of the Train Dispatcher to pass the signal. In the days before full coverage radio this could be a time consuming operation.
To my knowledge, no tower or control point was ever 'shared' between Train Dispatcher control and operator control.
Grassilli Tower in East Chicago was manned part time, but closed in November, 2007. It protected the switching movements of the EJE and IHB off of the IHB mainline and was open around noon.
The tower was recently moved to North Judson, In where it will be reassembled for inclusion in the museum. Work took me to East Chicago several times a week until last year and it was always assuring to pass Grassilli, particularly when a car was parked there (knowing the tower was still operating). Ditto for Calumet Tower a mile north which protects the CSX, EJE, and IHB crossing.
Now there is a tower I dont quite understand why it remains open...
Paul:That report is a must read for those who are interested in the operations of railroads and the problems/challenges which exist. It has been a few months since I read it...thanks for the link, when there is a little time I will return to it.
Now, what would REALLY be interesting would be a master plan for Chicago. The CREATE project is fascinating, but obviously well guarded without much information available.
blue streak 1Anyone:: Isn't there a few towers around the country that are manned during times of local high useage (ex. constant switching moves across diamonds, etc) and then remote dispatcher controlled at other times?
Not that I am aware of.
blue streak 1Railway ManI don't see JB Tower in W. Chicago becoming an automated crossing any time soon. RWM: Although I do not know the geography of that location your statement appears correct. Now one other reason I want to ask about. Would this tower and others in the Chicago area be waiting for CREATE to go into high gear? If this tower and others will be completely eliminated within ten years wouldn't it be more cost effective to wait? Then the UP could dispatch METRA and UP on its own tracks and CN (EJ&E) would fly over the UP? Do you have a WAG of how much automating West Chicago would cost? Also wouldn't the proposed HSR (no wag on when construction will start) also require the various RR lines to be grade separated? Another reason to wait?
Railway ManI don't see JB Tower in W. Chicago becoming an automated crossing any time soon.
RWM: Although I do not know the geography of that location your statement appears correct. Now one other reason I want to ask about. Would this tower and others in the Chicago area be waiting for CREATE to go into high gear? If this tower and others will be completely eliminated within ten years wouldn't it be more cost effective to wait? Then the UP could dispatch METRA and UP on its own tracks and CN (EJ&E) would fly over the UP? Do you have a WAG of how much automating West Chicago would cost?
Also wouldn't the proposed HSR (no wag on when construction will start) also require the various RR lines to be grade separated? Another reason to wait?
I won't comment on the costs of the tower in question or what strategies could be or should be. But, in round numbers, remoting a big tower will cost $5-$20 million, for construction costs (new signal equipment) and demo of the old stuff. Labor agreements, if any, are an additional cost.
A flyover is a $50-$250 million constructoin project depending upon how "clean" the site is. If it's a flat, open site with no land acquisition, no roadway grade separations, no utility relocations, no awful construction staging difficulties, no community impact costs (sound walls, roadway relocations, business relocations) then the number is on the low side of that range. If not, the number is on the high side of that range.
So, I had continue to make it priority to photograph as many towers as possible...and never turn down an invitation upstairs.
I agree with the earlier description of the antiquated environment of towers. In today's sterile office settings, it is somewhat refreshing to step back in time.
Railway Man henry6 As I said there is no reason they can't be remote controlled. Depending on the river traffic, though, many draws are manned only when there is a scheduled river movement. River traffic can be pleasure as well as commercial traffic. The point is not whether the technology exists to do something, the point is whether the USCG and USACE (and now DHS, too!) will be satisified that the technology will do the right thing. It's not so easy. RWM
henry6 As I said there is no reason they can't be remote controlled. Depending on the river traffic, though, many draws are manned only when there is a scheduled river movement. River traffic can be pleasure as well as commercial traffic.
As I said there is no reason they can't be remote controlled. Depending on the river traffic, though, many draws are manned only when there is a scheduled river movement. River traffic can be pleasure as well as commercial traffic.
The point is not whether the technology exists to do something, the point is whether the USCG and USACE (and now DHS, too!) will be satisified that the technology will do the right thing. It's not so easy.
Agreed.
I don't think it's too complex to remote. There are more complex, busier, interlockings remoted than this one. A joint manning scheme would create complex labor agreement, liability, and efficiency problems. It's been done but it's not fun; why create work and problems? Joint-facility agreements spell out priority of trains; it's not necessary to rotate staff to favor one road over the other. RWM
I don't think it's too complex to remote. There are more complex, busier, interlockings remoted than this one. A joint manning scheme would create complex labor agreement, liability, and efficiency problems. It's been done but it's not fun; why create work and problems? Joint-facility agreements spell out priority of trains; it's not necessary to rotate staff to favor one road over the other.
Thank you for answer regarding joint tower operation. Your point is well taken that it's more trouble than it's really worth. My interpretation regarding the word "complex" was meant to be all inclusive towards the interlocking plant, number of trains, train movements, the "J" being taken over by CN, etc. and not just the physical interlocking plant. One day JB tower will be gone, but not in the near future.
henry6As I said there is no reason they can't be remote controlled. Depending on the river traffic, though, many draws are manned only when there is a scheduled river movement. River traffic can be pleasure as well as commercial traffic.
BaltACDIrrespective of any Joint Facility agreements and what they may specify. The operator at a Tower or the Train Dispatcher who has direct control of a railroad crossing at grade knows whose name is printed on their pay checks and will give their employer all reasonable (and sometimes unreasonable) priorities.
Irrespective of any Joint Facility agreements and what they may specify. The operator at a Tower or the Train Dispatcher who has direct control of a railroad crossing at grade knows whose name is printed on their pay checks and will give their employer all reasonable (and sometimes unreasonable) priorities.
I had a recent experience with a major joint-facilities agreement regarding a tower. I made exactly that point to my railway. My railway had an unusual opportunity to change the agreement and gain control of the tower, which lies on a critical corridor with huge train volumes. The answer back to me was, "No, we'll live with the other railway keeping control of the tower, because the method you propose to gain control might set precedence elsewhere and we might not like the tables being turned in another situation. We think the language in the joint-facilities agreement is strong enough to protect us."
Time will tell.
Chris30I don't see JB Tower in W. Chicago becoming an automated crossing any time soon. The operations there are just too complex. Multiple grade crossings next to the diamond / tower make it more interesting. Even though the "J" operated the tower, the UP dispatcher (#11) dictated most of the movements through there because there were only a handful of "J" freights and trackage rights trains. Now, with CN taking over and wanting to run up to thirty trains a day through W. Chicago I expect some issues in the near future. I'm not sure if it can be done but the UP and CN might want to work out some type of joint operation with employees from both railroads working the tower on different shifts. It would make sense to have a UP employee operate the tower on the first and second shifts due to the Metra traffic and a CN employee cover the third shift because I expect a majority of the CN freight will move at night. CC
I don't see JB Tower in W. Chicago becoming an automated crossing any time soon. The operations there are just too complex. Multiple grade crossings next to the diamond / tower make it more interesting. Even though the "J" operated the tower, the UP dispatcher (#11) dictated most of the movements through there because there were only a handful of "J" freights and trackage rights trains. Now, with CN taking over and wanting to run up to thirty trains a day through W. Chicago I expect some issues in the near future.
Randy StahlDrawbridges are considered interlocking plants as well .... I don't think they will remote control all of them anytime soon .
Drawbridges are considered interlocking plants as well .... I don't think they will remote control all of them anytime soon .
The Coast Guard can make it difficult to remote drawbridges. The "safety" and "right-of-way" requirements can be so onerous that there's no good technical solution that will satisfy the USCG, even though the man sitting there reading magazines doesn't necessarily accomplish what the USCG demands, either. The government seeks a zero-defect environment where no change can be approved unless it's perfect, because the last thing it wants is some tiny thing to go wrong and get called out by the media mouthpieces. That's a career killer. So instead we have to make do with old, expensive, and highly imperfect solutions. We can live with 80% but God help anyone who proposes 95% instead of 99.99999999% solutions.
MP173Railroad towers have always been fascinating to me. These days what little railroad photography I do is often based on locating and photography existing towers, either in service or retired. Fortunately in Chicago and NW Indiana there are still several towers still in operation. To gain an invitation inside is very rare, but quite a special experience. Ok, this is not about nostalgia, but rather the functionability of towers at certain junctions. At a fairly busy or complex junction, such as Fostoria, is it more efficient to have local control, in form of a tower and operator rather than centralized dispatch hundreds of miles distant? Perhaps my question is better phrased as "does a local tower operator keep the traffic moving more efficiently than central dispatch?" I fully understand the cost consideration involved and the labor saved, but there sure seem to still be a number of towers still in existance. Why? (hopefully this will not jinx those still in operation). ed
Railroad towers have always been fascinating to me. These days what little railroad photography I do is often based on locating and photography existing towers, either in service or retired.
Fortunately in Chicago and NW Indiana there are still several towers still in operation. To gain an invitation inside is very rare, but quite a special experience.
Ok, this is not about nostalgia, but rather the functionability of towers at certain junctions. At a fairly busy or complex junction, such as Fostoria, is it more efficient to have local control, in form of a tower and operator rather than centralized dispatch hundreds of miles distant? Perhaps my question is better phrased as "does a local tower operator keep the traffic moving more efficiently than central dispatch?"
I fully understand the cost consideration involved and the labor saved, but there sure seem to still be a number of towers still in existance. Why? (hopefully this will not jinx those still in operation).
The answer is that certain towers have joint-facility agreements that make it economically or strategically unfavorable to close the tower and remote it to a dispatching office. Because until someone proves to me otherwise, I know of no tower that can't be remoted and trains run more cheaply and just as efficiently if not more efficiently than by a manned tower. The only advantage a manned tower has is the ability to look out the window, and that's not of much use unless the railroad is running with a smoke-signal mentality.
Example. Suppose XYZ Tower controls the crossing of Railroad A and Railroad B. Railroad B arrived second, and to obtain permission to cross Railroad A, it agreed to build, staff, and maintain the tower, but the cost was allocated on the basis of train movements through the plant. Total cost is divided by number of train movements to derive per-train cost, then multiplied by the number of trains for Road A and Road B, and each pays their share. Suppose the agreement also says that future upgrades or changes are to be allocated according to train use -- a reasonable clause, don't you think?
Now suppose today that Railroad A runs 99% of the trains through XYZ Tower and Railroad B 1%. Cost to Railroad B is nil; in fact, it probably is finding ways to turn a profit on the tower by allocating all sorts of shared expenses in the vicinity to the sole expense of the tower. Obviously Railroad A would love to be rid of Tower XYZ, but Railroad B wants to keep it, especially since it can be a subtle thorn in Railroad A's paw. Railroad A approaches Railroad B and says, we want to be rid of the tower. Railroad B says, fine, you pay 99% of the cost to remote it to our dispatching center, no problem. No, actually, says Railroad A, we want to remote it to OUR dispatching center because we run most of the trains through there. Hmm, we'll get back to you on that says Railroad B, because we think our agreements with the locals will make it sticky to give jobs away to another railway. What Railway B is really saying, is , "What, and give up an opportunity to stick it to you when you stick it to us over at the junction at ABC?"
And so it goes. When the pain level gets bad enough, Railroad A will give Railroad B what it really wants, which is a horse-trade of something someplace where it is at Railroad A's mercy, or cash, or both. Note that the old agreement which was highly disfavorable to Railroad B now comes back to haunt Railroad A. No good deed goes unpunished.
You can make a career at railways being expert in joint-facility agreements, and I've sat there and watched awestruck as some people making enormous salaries have gotten it totally wrong and given away the store to another railway whose negotiating position was built around a high card five of diamonds.
Note: There's a separate issue discussed subsequent to your original post which is, "Is it better to have local operational control than distant control." That is a question to which there is no perfect answer. At the extremes, the answer is clear -- 100% remote operation doesn't work out too well, and 100% local operation doesn't work out too well either. But where exactly to draw the line in the middle is difficult to figure out, and because the world is dynamic the line moves around on a daily basis. Railroads have been finely tuning that line for years, and not a week goes by that I don't learn about some new initiative to centralize something that used to be local, or localize something that used to be centralized. The change is usually painful for all involved, and whether it's for the better is hotly debated. Just last week I saw what I thought was a pretty good centralized program (not train control) get regionalized because the regional heavy-hitters were feeling miffed that they didn't have enough control over their regions.
I would say that for train control, I have long been a proponent of localized operational control, but the older I get the less enamored I am with localization or regionalization because it is so hard to find talented, smart people who will do it right and not turn their job into a little kingdom that refuses to play well with others. If you're at the bottom of the totem pole you tend to like regionalization, and if you're at the top you tend to like centralization. The higher I get kicked up the totem pole the more I want to be able to actualize the power I supposedly have.
But they can be...and are. Remote cameras, scheduled openings, etc. Lots of abilities to do it.
Back in the 1960s, I discovered an interlocking tower out in the pastoral countryside of Eden Prairie, MN. The operators were friendly, and I spend a lot of time there waiting for trains to ring in and hammer across the frogs. The first time that I was invited inside, I was struck by the incredible feeling of antiquity. The office and interior just seemed downright ancient.
The first story was brick, and one of the operators once showed me all of the names, dates and messages that were carved into the soft brick. There were maybe over one hundred of them. People who had worked there fifty years earlier had left carefully engraved little monograms. On one side of the tower, there was somewhat of a small lawn and garden with mowed grass and colorful lilies.
The interlocking plant had 24 levers, but many were taken out of service because some of the trackage had been removed years earlier. But what was really amazing was to learn that the tower had originally been built in an entirely different location. It was built in 1880 to protect an M&StL/CM&StP crossing. In 1913, the roadbed of the CM&StP was improved and relocated, thus changing the crossing location. So the tower was picked up, skidded down the tracks, and placed on a new foundation at the new location, about a mile away.
After becoming so familiar with that tower in the modern age, I have wondered what it was like in its original incarnation where it served its first 33 years. What kind of interlocking plant and semaphores were used there? How were they illuminated in 1880? Did the operators ride horses to work?
Simple. Towers (not all "towers" were towers, some were non-elevated shacks, some were inside stations, etc.) were placed where there was a confluence of tracks, usually more than two tracks and definitely more than one switch. The towers operated the switches by electricity, air, or (first)mechanically by "strong arm" plants so that all switches and signals in a given interlocking location could be minipulated from one point. The switches and the attneding signals were interlocked so that no conflicting movements could be made; usually within a quarter of a mile (strong arm) to maybe up to a mile and a half (electric, air). Eventually C.T.C. was developed which allowed, by electricity, electronics, and telecommunications, that an interlocking location could be manipulated from an infinite distance. The more sophisticated the electronics, the more intracate the interlocking which could be remotely controlled. I really can't fathom how today, one man can operate several complex interlockings of a commuter system at from one location all at the same time. But I do see it is done with very little difficulty and complete success.
Our community is FREE to join. To participate you must either login or register for an account.