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Thursday, June 21, 2012

'C' is for Stop and Check

Some may make fun of the "diversity" of North American signal rules, but they do make for interesting explanations. Today's post brings us to the southern portion of the country for a signal rule unique to the former Seaboard Air Line territory of CSX. The rule in question is 293 which applies to any all red signal with a (C) plate attached to it.

Image

The rule itself reads.

Stop and check position of drawbridge, spring switch, derail, gates protecting railroad crossing, ensure the way is clear and drawbridge, spring switch, derails, or gates are in proper position and proceed at Restricted speed

The rule sounds simple enough, sort of splitting the difference between a Rule 292 Stop signal and a Rule 291 Stop and Proceed signal. However, to fully understand Stop and Check and the reasons for its use you have to place yourself in the context of the single line, train order based system of operation that predominated in much of North America up until the 1960's. Growing up in the Northeast with its heavily industrialized past it is easy to develop a rather bias view of what railroading should consist of. I.E. Main lines have 2 (or more) tracks, signaled with ABS and interlockings (manned or otherwise) are plentiful, especially at main line diamond crossings and movable bridges. Secondary tracks can be single and controlled by manual block or train orders, but its not such a big deal because those are the old agricultural lines that don't even exist any more. Maybe if a railroad was trying to pinch pennies that might employ something with Absolute Permissive Block with swing switched passing sidings and holdout signals, but that's more an interurban thing. This point of view would also apply in Europe.

Unfortunately this reality only existed where industrial and population conditions allowed for it as things like two track main lines and interlockings are big ticket items that railroads serving areas that consist mostly of empty land or farm fields simply could not afford. In these places the model was single track main lines with passing sidings and some bi-directional ABS if you were lucky. Interlockings were few and far between with diamond crossings and movable bridges getting no special pass on this. Oh, and trains dispatch themselves working with timetable and train order. For a system that did whatever it could to eliminate the need for full fledged interlockings, Rule 293 Stop and Check is to diamond crossings and movable bridges as spring switches and absolute automatic hold out signals are passing sidings.

Stop and Check plated signals are automatics in that there is no human that can push a button and set them to absolute Stop, yet they are attached to things that might often require an absolute stop like diamond crossings and movable bridges. However they can get away with this because what Stop and Check protects does not represent a decision point for the train. Instead of spending money to install an interlocking that must have routes set by a human and must require human intervention in case of a failure, Stop and Check allows train crews to inspect local conditions on their own and continue without external input.

Now the usefulness of Stop and Check is clear in the old Train Order days, but why would they appear on modern CTC lines? Well under early modern CTC schemes where Stop and Check is likely to appear there are several factors at play. First you'll still save money using Stop and Check than installing an interlocking. Second, the majority of railroads outside of the Northeast industrial belt did not adopt a Call-on aspect as standard in their CTC interlockings so if there was a problem affecting the ABS logic of an interlocking a signal could not be displayed even if the routing logic checked out. Passing such signals would require dispatcher intervention, which on a low density line isn't a huge problem, but the more absolute signals one installs, the greater the potential for disruption. Finally, simply fitting an old train order operation main line with CTC doesn't necessarily eliminate the old train order mentality. The line is still single track with short passing sidings. Fitting fully fledged interlockings in the space between these sidings only allows for dispatchers to screw up and create Mexican standoffs at the movable bridge or diamond crossing. Since routing decisions can only be made at passing sidings there is no reason to allow dispatchers to exercise control at intermediate points unless there is an explicit need for a holdout signal.

Alright then, I think this is a pretty good investigation of the context behind Stop and Check so let us look at a real life example located in Athens, Georgia where the CSX Abbeville (nee SAL) crosses the former Central Railroad of Georgia Athens branch crossed. Today the old CoG line is run by a shortline serving local industries north and south of the city. It sees nowhere near the level of traffic as the Abbeville Sub does and therefore there is no need for full time mediation of routes at the crossing. The crossing is also one block north of Fowler Junction passing siding and while a holdout would be appropriate here, it was not seen as necessary.

We begin looking north along the Abbeville Sub and one thing in our immediate favor is that for whatever reason these signals are not approach lit so unlike every other signal on this line we are treated to constant stream of block occupancy and direction of traffic information. Also in evidence is a solar powered rail greaser, and a call box that may or may not still be in operation. Keep in mind this is not an interlocking and as such has no station name associated with it. It's only reference in the employee timetable is on the diagram and there are no special instructions regarding a "railroad crossing at grade. So for train crews the only thing special about this location s that (C) plate.



Tuesday, June 19, 2012

RIP ALTO: 1915 - 2012

Not sure what else needs to be said.  As expected the Railroaders museum will get a chance to preserve it, but is will not be in situ so the elderly wooden tower will need to survive a move across the street.  Let's hope it makes it like BOWIE tower instead of MO Tower (in Cresson, PA), which fell apart when the crews began to move it.  The new interlocking has been named CP-ALTOONA and combines the function of both CP-SLOPE and ALTO.  CP-WORKS, CP-HOMER and CP-ANTIS have all been re-signaled and CP-ROSE has been removed.  Where will NS strike next?  Who knows.

ALTO Tower 1952.


ALTO Tower 2012.


Friday, June 8, 2012

Updates: BNSF and D&H, Bad News All Around

Leading off, if you remember a few days ago I posted that Canadian Pacific had abandoned its policy of replacing old three head searchlight stacks on its former D&H main line with similar Unilens units and instead decided to abandon all sense of style and just go with Darth Vader types.  Well it appears that what was sighted at CPC-100 was not an isolated replacement, but instead part of a whole line re-signaling that has now reached the signals at CPC-37, including the widely photographed D&H bracket just north of the Saratoga Springs Amtrak Station


So much for the authenticity of the Saratoga and North Creek tourist operation.  Anyway, the re-signaling is going to spare the recently re-signaled plants like CPC-36 and CPC-481, concentrating on the relay logic plants in order to aid PTC adoption.  (See why the signal vendors were lobbing so hard for this?  Cost effective "overlay" my ass!)  The fate of the plants that recently had signals replaced without back end improvements remain to be seen.  What is even more unfortunate is that CP is piling cheap upon cheap and installing signals unable to display bottom yellow Restricting indications for many of the routes.  At least CSX gets some credit for rectifying this oversight on the former Seaboard system interlocking plants it is "upgrading."

The saving grace for the former D&H main is that all of the automatic signals have already been replaced with searchlights of the Unilens type and modern relay and track circuiting equipment.  Moreover the line has one passing siding per 20 route miles, instead of the usual 7-10 so a majority of the signals will stay Searchlit.  Still, its a shame that CP couldn't stick to its guns and continue providing the D&H with a higher quality signaling experience, even if that meant LED searchlights (which are not being given a fair shake IMHO). 

Second update comes on former CB&Q Main Line where pole-line serviced searchlights mounted mostly on two track gantries have been under attack for the last couple of years.  While that replacement was long in coming, it appears that the Altoona of the CBQ is also facing extinction with the A, B and C plants at Galesburg now under a death watch despite lack of pole line feed.  What a waste.  Good news here is I'm scheduled on a Zephyr trip and should be able to document them in time.


Monday, June 4, 2012

Odd Stuff at Night

I wanted to quickly take the time to show some really fascinating signal related photos I came upon in the last few weeks.  The first was taken at Willowtown, WV on the old Norfolk and Western main line and shows a pair of classic N&W CPL bracket mast automatic signals.  What makes this photo especially cool is that it helps to counteract the conventional wisdom that N&W CPLs are equivalent to Amtrak's colourized position lights.  While the upper head of an N&W CPL is the same as the Amtrak variety, the lower head makes use of all yellow (not Amber) lights (except for the central red marker on absolute signas).  You can see this for yourself in this photo that shows an Approach Diverging signal on the bracket next to a Clear signal.


The next pair of examples show the C&O's absolutely bizarre implementation of a diverge to stop aspect.  Before the advent of reliable flashing relays, most railroads that wanted to use a lower head yellow for Restricting had to kludge how they handled diverge to stop (Medium Approach, Slow Approach) aspects.  Some, like the New York Central, simply used three signal heads on all signals, other used ground mounted subsidiary signals while the PRR simply had trains diverge over Approach (or Slow Approach).  Well the C&O was to have none of this and for their Medium Approach they added a second yellow lamp on the lowest head as seen here in this photo near Fostoria.


What is the reason for this?  Well it makes sense when you see that Slow Approach is R/Y/R, compared with Restricting R/Y (over Dark).  Yup, the C&O was so committed to the Restricting yellow on the second head they actually will light up a red lamp to upgrade the signal...crazy!!!  Here is a Slow Approach example at Fostoria.


Friday, June 1, 2012

CSX Chicago Line Resignaling

If obtained some more information on CSX's resignaling plans on the former Conrail Chicago Line in upstate New York.  In the east CSX is planning to cut over new signals from CP-RJ (Rotterdam Jct) to CP-175 (Amsterdam) on July 1st.  Not only will this wipe out the famous junction at Hoffman's (CP-169), but one of the few remaining NYC style cantilever masts.  Moreover I confirmed that CSX is changing over the signal rule set from NORAC to Seaboard.  This change was already put into effect on the Selkirk Branch back in 2007 and will slowly be making its way out along the entire route. 

In addition to that there is a larger project under way out between Syracuse and Rochester, but unlike other parts of the Chicago Line, was last updated under the Penn Central instead of Conrail and now CSX has almost the entire Rochester Sub targeted for replacement as well as a ruleset change.  As you can see in this image from CP-335 in Lyons, NY some of the interlockings still have local pole-lines between the appliances and the relay hut.


And here is a video taken at CP-334 you can see former NYC bracket masts and the new signals set to replace them.




The real shame is that with baggage cars riding the back of the Lake Shore and rear cars frequently being closed on Empire trains there isn't a very reliable method to survey the line without multiple attempts and/or staying overnight in the Buffalo area.