and I saw again those towers many of us miss and which often had a friendly guy whose job it was to get up from his desk, walk across the room and start to yank on a lever, pulling it all the way back (or pushing it forward). To a boy this looked like very difficult physical work; no one ever seemed to do it all in one motion, but with a jerking effort and needing almost every tooth in the ratchet.
So, a few questions come to mind, starting with How difficult was it? Did towermen have to pass a strength test of some kind? Whose job was it to keep the levers and rods greased up, and how often? What happened when a lever just couldn’t be pulled because of say, cold? Or would go only part way? How far ahead of the needed time was a switch required to be thrown? Did seldom used switch rods and levers tend to rust and become more difficult or even impossible to throw? Were some levers more difficult to use than others in the same rank?
And what was it about those very shiny-from-long-use lever handles that just made one want to put one’s hands on them?
I would think that the effort required in moving the levers also depended on how much pipe between the tower and switch needed to be moved and how many joints were in the connection.
Not all Armstrong levers performed the same purpose or activated the same appurtances. In general there were three types of level activations - throwing a switch or crossover; locking the switch or crossover in place; lining the signals through the plant with the route having been lined and locked in place to allow the signal to be lined.
Normally, each interlocking had a Signal Maintainer assigned to it and he was responsible for all maintenance actions for the plant as well as being the in
I’ve always wondered how many of those towers got converted to power switches but retained their interlocking levers. Did many? most? “armstrong” levers in, say, 1960 not connect to any outside rods?
I’ve read that the entire CSX railroad is run out of an office building in Jacksonville and there are no more towers. Does that include every track turnout? Or only on main lines? Yards?
Even on the Main Lines there are Main Track crossovers that have not been made into Control Points with signaled and power operated switchs.
Main tracks with track speed above 20 MPH with hand throw switches are required to have those hand throw switches electrically locked IF - trains/engines are going to be cleared up on those tracks.
Yardmasters/Hump Retarder Operators control power switches within the Yard.
A possibly related question: many, if not all switches on main lines are required to have PTC position (and possibly condition) indication, whether or not power operated. Are all those indications on CSX ‘remoted’ to Jacksonville? If so, how are they polled and displayed?
The only switches appearing on the CADS model board displays are those that the Dispatcher controls either by being power operated or by having a Dispatcher controlled Electric lock. The display on the model board for a Dispatcher controlled electric lock is a icon unique to the function, not a switch representation.
Switch position indications are communicated directly between the PTC controller on the hand operated switch and the PTC equipment on the locomotive; that communication does not go through the CADS system.
Many main track hand throw switches in signalled PTC territory ARE NOT directly linked into PTC. Where PTC is an overlay using the existing block signal system for occupancy, it is possible to open a switch after the train/engine has passed the governing signal for the block the switch is in and PTC status will not change.
If a switch is opened before passing the signal governing entrance to a block, the signal will show it’s most restrictive indication. Then when a train/engine travelling through that block at restricted speed approaches a hand throw switch, about 400 feet from the switch, PTC will query the engineer on the position of the switch. Facing point switches require choosing between a normal or diverging route option. Trailing point switches just ask for verification.
Cab signals will immediately show a change in condition of the block the train is in. UP has petitioned the FRA to discontinue both ATC and CCS cab signal systems. UP says before discontinuance they will “wire in” the hand throw switches to display switch status in PTC. While neither ATC or CCS has been discontinued, UP has a waiver to operate without either system if PTC is operative. We still need an equipped (ATC and/or CCS) leader that has passed a departure test to lead in the respective territories. But if PTC is operative, ATC/CCS is cut out.
At Stanwood, IA a couple of summers back a hand throw switch to a stub track, remains of a former siding, was opened in the face of a coal train. PTC didn’t register the swi
and I saw again those towers many of us miss and which often had a friendly guy whose job it was to get up from his desk, walk across the room and start to yank on a lever, pulling it all the way back (or pushing it forward). To a boy this looked like very difficult physical work; no one ever seemed to do it all in one motion, but with a jerking effort and needing almost every tooth in the ratchet.
So, a few questions come to mind, starting with How difficult was it? Did towermen have to pass a strength test of some kind? Whose job was it to keep the levers and rods greased up, and how often? What happened when a lever just couldn’t be pulled because of say, cold? Or would go only part way? How far ahead of the needed time was a switch required to be thrown? Did seldom used switch rods and levers tend to rust and become more difficult or even impossible to throw? Were some levers more difficult to use than others in the same rank?
And what was it about those very shiny-from-long-use lever handles that just made one want to put one’s hands on them?
Not all Armstrong levers performed the same purpose or activated the same appurtances. In general there were three types of level activations - throwing a switch or crossover; locking the switch or crossover in place; lining the signals through the plant with the route having been lined and locked in place to allow the signal to be lined.
Normally, each interlocking had a Signal Maintainer assigned to it and he was responsib
As I’ve understood interlockings, the plant was designed so things could only happen in a given order, much as Balt wrote.
There was a mechanical block that prevented lever A from being moved until lever B was moved, etc. That included signals, locks, you-name-it. Hence the “cheat sheets.” Of course, at a single location there would likely be only a given number of possible movements.
The bigger passenger stations were, of course, an animal in and of themselves.
Once the armstrong levers were replaced by switches, relays handled that blocking.
[quote user=“Semper Vaporo”]
I appreciate the human interactions that had to occur in altering a switch, but I think you left out the mechanical interactions.
I am not sure of all this, but as I understand how the old Armstrong systems worked, the operator could not just pull a lever to alter a switch position… that lever would be mechanically locked in some maner and that lock had to be released first.
The operator first had to change a lever to alter a signal ahead of the switch to be altered, so any approaching train had to stop or reduce speed so it could stop before reaching the switch. That also triggered a timer of some sort (possibly a pnumatic or hydraulic dashpot or maybe a spring driven clockwork) that had to “time out” before unlocking the lever for the switch to be changed. This was so that any train that had passed the signal would have time to reach the switch and it would be in the position the train expected for what the signal displayed when it was passed.
That Timer would be long enough to account for the slowest train to traverse the distance at “track speed” for that area. If the train was moving slower than that, the engineer would have time to stop the train if the switch was not in the expected position.
Once the Timer completed, then the desired lever would be released so the operator could change the switch position. Then that signal ahead of the switch could be set to indicate the new position of the switch, telling any approaching train what to expect.
In addition, the system was reset such that another timer was started that prohibited the operator from changing the switch position until he changed the signal indication such that a train that might have passed the signal already would not find the switch in other than the expected condition based on what the signal had indicated when passed.
A possibly related question: many, if not all switches on main lines are required to have PTC position (and possibly condition) indication, whether or not power operated. Are all those indications on CSX ‘remoted’ to Jacksonville? If so, how are they polled and displayed?
Many main track hand throw switches in signalled PTC territory ARE NOT directly linked into PTC. Where PTC is an overlay using the existing block signal system for occupancy, it is possible to open a switch after the train/engine has passed the governing signal for the block the switch is in and PTC status will not change.
If a switch is opened before passing the signal governing entrance to a block, the signal will show it’s most restrictive indication. Then when a train/engine travelling through that block at restricted speed approaches a hand throw switch, about 400 feet from the switch, PTC will query the engineer on the position of the switch. Facing point switches require choosing between a normal or diverging route option. Trailing point switches just ask for verification.
Cab signals will immediately show a change in condition of the block the train is in. UP has petitioned the FRA to discontinue both ATC and CCS cab signal systems. UP says before discontinuance they will “wire in” the hand throw switches to display switch status in PTC. While neither ATC or CCS has been discontinued, UP has a waiver to operate without either system if PTC is operative. We still need an equipped (ATC and/or CCS) leader that has passed a departure test to lead in the respective territories. But if PTC is ope
Where I run, PTC doesn’t know the position (closed or open) of hand-thrown switches. But it does know where they are, and if you are running on restrictings (as would be the case if a switch were open), it will not allow you to pass any switches while running under that restricting until you visually determine the position and confirm it.
That being said, even when running on clears I’ve had the system suddenly not know what a switch position is for some reason (even though I’m on a clear), and penalty brakes the train to stop prior to the switch. Unless it panics too late, then it may place your train into emergency.
If snow or some other visibility problem caused the switch position to be wrongly confirmed, then how does PTC prevent movement of the train thru the switch?
It’s not unusual to train watchers at Deshler to see the “Reservoir” southbound signal to go to “restricting” immediately after a train has passed southbound.
Normally that signal will eventually cycle though to “clear” before the next train arrives.
I conclude that the DS is thus able to line another train through as soon as the leading train has cleared the interlocker, with the “system” setting the signals appropriately.
There are a number of tools that the CSX Train Dispatcher has in using the CADS from Union Switch & Signal (aka Union Switch & Swindle). In addition to being able to Fleet multiple trains (up to 9) on the same route at a control point, there is also the Union Route tool which allows the Dispatcher to line multiple routes for trains in different directions as well as crossing over in front of each other.
Monday-Friday the morning VRE fleet of trains will have the Northbound signals on #2 track stacked and fleeted from Crossroads to AF (there are VRE Stations in each track segment between control points that can only be worked from #2 track without requiring special protection - Northbound or Southbound). From AF into Washington Union Station the stations permit VRE to make station stops from any track and movements will be interleaved with the VRE Manassas trains as well as CSX freight trains. The Manassas VRE trains come on to CSX at AF - there is coordination between the NS Train Dispatcher and the CSX Train Dispatcher on the handling of these trains in both directions as there are 3 tracks that can be used to move between CSX and NS at AF.
Note - on the RF&P (being a North-South railroad) tracks are numbered from the East t