ATSFGuyDidn't Conrail use Cab Signaling back east on former PRR lines?
Yes, and in many places without any form of 'train stop' associated with it.
Didn't Conrail use Cab Signaling back east on former PRR lines?
zardoz Otherwise it was mostly a PITA, as the occassional unwarranted and surprise penalty application (on a clear signal) had the potential to cause unwanted slack action (even more fun if there is a "kicker" in the train). When an Engineer sees a less-than-clear signal, he has the opportunity to adjust train-handling as necessary; but getting a penalty app while drifting along in the 3rd or 4th notch over undulating terrain is not desireable. I made it a habit to acknowledge every signal in ATS territory, thus preventing the aformentioned situation.
Otherwise it was mostly a PITA, as the occassional unwarranted and surprise penalty application (on a clear signal) had the potential to cause unwanted slack action (even more fun if there is a "kicker" in the train). When an Engineer sees a less-than-clear signal, he has the opportunity to adjust train-handling as necessary; but getting a penalty app while drifting along in the 3rd or 4th notch over undulating terrain is not desireable. I made it a habit to acknowledge every signal in ATS territory, thus preventing the aformentioned situation.
We have the same problem with ATC, getting false activations. It used to be bad in certain areas during wet conditions that we call it getting, "rain control."
The exCNW's ATC is clear or restricting. It's either full speed ahead or restricted speed. We don't have an option for advance approach (40mph) or approach (30mph) speeds. So when you're putting along at 70 mph, go by a clear signal and hit a section of dead track, The cab signal goes to restricting. You then have 6 seconds for one of the following to happen. One, the outage was temporary and the cab signal picks back up to clear. Two, if you can't ride it out you place the automatic brake into suppression. This makes a full service application but "suppresses" any penalty brake application. If neither happens, the ATC goes into penalty, takes your air at a service rate (not emergency) and opens up the PCS. Like Zardoz said, neither penalty or suppression application is good train handling. It has torn trains apart. Enough that we have a few manifest symbols that are restricted to 40mph if they are both over 6000 feet long and 10000 tons. 40 mph is our ATC's dividing line. If you are below 40 and get a restricting cab you have 70 seconds to get below 22mph. That's not always possible, but at least it gives time to make a more normal split brake pipe reduction which is better train handling. Prepares you if you still have to go to suppression.
Jeff
Few items
1. Deggestry is probably correct from what pictures have seen.
Here is where KP can be a big help
2. KP may have pictures of both BNSF and Metrolink ATS pickups. Do not recall Metrolink locos and cab cars with the pictured pickups.
3. There was a posted picture by KP (?) that showed an ATS inductor on the approach to some downgrade. The caption stated that it was a timed appliance that would give a stop until a certain time had passed from the activator. This operationally similar to NYCity subway train stop systems. Santa Fe's would stop trains from going too fast down grade.
4. Believe that the ACS on Amtrak motors requires an acknowledgement and slowing to prescribed speed ? Hasn't it been posted elsewhere that if 188 had encountered an approach signal instead of clear that the motor's ACS would have slowed the train to 60 ?
Then of course outside this thread's is PTC's protocols
jeffhergert ATC and ACS are continuous systems, through the rail, and their pickup gear is (on the UP/CNW) behind the pilot in front of the lead wheels. Yes, ATC monitors speed and enforces the speed required by the cab signal. Cab signals do not give the indication of the next signal. It gives the indication of the last signal you passed. A better way of saying it is this. A wayside signal tells you the condition of the block you are going to enter. The cab signal tells you the condition of the block you are in. I've never worked with ATS, but I'm not sure that it would intiate a penalty brake application if the engineer acknowledged the ATS and did nothing else. A plain cab signal system, like the UP's CCS, will intiate the application if the more restrictive cab signal aspect change isn't acknowledged. However, there is no speed component like with ATC. You could go from Clear to Advance Approach to Approach to Restricting without ever reducing speed as long as each change was acknowledged. I think ATS may be similar. I think Zardoz may have worked with the CNW's ATS. He would know better than I about that. Jeff
ATC and ACS are continuous systems, through the rail, and their pickup gear is (on the UP/CNW) behind the pilot in front of the lead wheels.
Yes, ATC monitors speed and enforces the speed required by the cab signal.
Cab signals do not give the indication of the next signal. It gives the indication of the last signal you passed. A better way of saying it is this. A wayside signal tells you the condition of the block you are going to enter. The cab signal tells you the condition of the block you are in.
I've never worked with ATS, but I'm not sure that it would intiate a penalty brake application if the engineer acknowledged the ATS and did nothing else. A plain cab signal system, like the UP's CCS, will intiate the application if the more restrictive cab signal aspect change isn't acknowledged. However, there is no speed component like with ATC. You could go from Clear to Advance Approach to Approach to Restricting without ever reducing speed as long as each change was acknowledged. I think ATS may be similar.
I think Zardoz may have worked with the CNW's ATS. He would know better than I about that.
The inductor was bolted to the ties at a point where the receiver (mounted on the front truck, similar to the OP's photo) such that the two would be aligned when the locomotive cab was next to the signal mast, although far enough back that the Engineer could easily still see the signal.
It was a great system in inclement weather where visibility is severely restricted: if you miss a signal due to dense fog or heavy snow (especially when the snow is being blown in to the signal shroud and is sticking to the lens), the ATS system would bring the train to a stop.
But it was better than nothing.
The history of automatic train control is long and interesting (I wrote my college thesis on part of it) and becoming more interesting every year.
As part of the restoration of the railroads to 'private control' after WWI, the opportunity was seen -- and taken -- to incorporate rollout of automatic train control of some kind (legislated as the Esch Act of 1920). As with other unfunded mandates involving new and comparatively untried technology, the idea was to allow railroads to try or buy any technology that met the stated requirements, and to equip one test division somewhere on their system with it. This would then after a certain number of years extend to two divisions, then more, on the sort of timetable (and with the sort of extensions!) we have seen repeated with the PTC law. Extension of the thing was thrown over in 1928 (in favor of greater grade-crossing safety and elimination as a priority) leaving the railroads responsible for keeping what they had implemented. (This is where the '80mph and above' language familiar after the ICC order of 1947 came from)
The idea, in part, was that private industry, in no small part the burgeoning radio equipment industry, was expected to pick up on this rich source of new business, and evolve both the technology and the systems used to implement it. One very interesting company was founded by Frank Sprague (of MU and elevator-control fame). The usual conflict between proprietary technology and interworkable standards was present, so you shouldn't be surprised to find different types of equipment, locations for pickups, or actuators and control.
ATS is a system that applies the brakes to stop a train when it does something 'unsafe'. The most obvious form of this is in block-signal control, where 'running a red block' does the equivalent of what the pneumatic trippers on NYC subway cars do. For various technical reasons, using electromagnetic induction between track and vehicles made better sense than physical contactors. It was of course possible to extend the functionality of ATS by incorporating some form of 'speed limit', but this worked in the general way alluded to above, where an overspeed that was not 'acknowledged' or 'forestalled' would produce effectively the same trip as running a signal, and have the same general requirement that the train come to a full stop and the system reset from well outside the cab.
ATC is different because it performs more intelligent control: for example, reducing speed to the 'correct' range called for by a change in signal aspect, or reducing overspeed in the manner of a governor when traveling too fast. This is related in many ways to the provision of cab signals, but the two fields of development should be regarded as separate (as they were often kept separate in practice, sometimes for political reasons)
Michael Savchak, a friend of David Schanoes, has compiled a good selection of references on automatic train control, which might be of interest to some of the people reading this topic.
Thanks, Jeff--especially for correcting my understanding of ACS.
Johnny
ATSFGuy What are those pickups used for? I always thought that extra "piece" hanging was part of the locomotive's braking system.
What are those pickups used for? I always thought that extra "piece" hanging was part of the locomotive's braking system.
Automatic Train Stop comes into play, usually at a signal, if the engineer does not reduce speed, or stop, (according to the signal aspect).
Automatic Train Control is a continuous sytem, which continuously monitors the speed of the train, and acts to correct an engineer's failure to run the engine properly (Jeff, am I right?)
Automatic Cab Signaling is a system that provides signals within the locomotive cab (formerly on the engine's backhead) which give the indication of the next signal. It can be used witout actual lineside signals.
The picture of the SFe ATS shoe in a post on the Super Chief Fueling Stops thread intrigued me because it does not look like the shoes that the Southern had on its engines. Apparently, more than one company made ATS equipment--and had different placing of the lineside coils. The Southern's shoes were mounted lower, and the lineside appliance was a little farther from the rail, and was like a ramp.
At least one other road used the same system that the Southern used--the section of the Northern Alabama RR the IC used to reach Birmingham (Haleyville to Jasper) had ATS--and no other part of this road had it. Did the Frisco (also used by the IC into Birmingham) use the same system?
It seems to me that some roads had the pickup beneath the locomotive, but I may be mistaken.
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