Data Infrastructure Increasingly Substitutes for Radio Comms

I have been reading reports that as PTC systems are being certified for operation, their data transmission facilities are being used to transmit various mandatory directives such as Track Warrants, Temporary Speed Restrictions and Work Limits. Moreover, company issued electronic devices are also being used to send the same type of "paperwork" in various electronic formats. Previously read over open channel VHF radio to be copied and repeated by the crews, the new methods keeps the information off the air with the radio link only being used to confirm delivery.

 

Although a loss for the scanner community, delivery of what I will call "train orders" has used closed communications channels since the first telegraph line was established to replace a pure timetable system. Hand and telephone delivery have always represented a small, but durable portion of train order transmission since radio communications became a thing in the 1970's. Closed communications channels have long been the norm in Europe using a dedicated GSM-R band set up for the purpose.

I would still anticipate policies on train order transmission to evolve as one of the greatest benefits of open channel communications is the situational awareness provided to all manner of right of way workers and train crews who may wind up at the wrong place at the wrong time. There are countless stories of accidents averted because someone was tipped off to an unsafe situation through radio chatter and is also one of the reasons signal calling remains a thing.

It will be also interesting to see how the scanner community adapts and if PTC deciding will become a thing like ATCS decoding. Although not as open as analogue VHF, there are no FRA requirements to encrypt PTC data, only requirements to authenticate safety critical data. What the industry has decided to do remains to be determined, but with locomotives needing to be able to operate across the national network it is highly likely that industry will seek to minimize the certificate management problems. It is also likely they will just do a bad job resulting in security that is easily exploitable.

Wrong Railing Across the Pond

How many Full Time Employees does it take to run a train against the flow of traffic on a section of double track manual block signaled track? Well the answer depends on which side of the Atlantic Ocean one finds themselves on.  In North America the answer is between three and one.  You can have a dispatcher transmit train orders to block operators on either end of the segment or simply use a radio to transmit the orders directly to the train.  However in the United Kingdom the answer starts at 3 and increases from there. 

In mechanically signaled manual block territory you first need to employ signalmen at either end of the track segment.  Then all wrong direction movements need a pilotman to chaperone all trains through the section of single track operation.  Back in the day when stationmasters were still in existence both of them had to be informed so that is a total of five workers.  Then because most block stations were only equipped with non-locked trailing point crossovers you needed another two men to spike and wedge the points prior to a train movement.  Finally where main line spring worked catch points were employed you needed another person to spike and wedge those as well. The total number comes out to between 5 and 9 depending on the circumstances.  Of course the one thing they don't have is a dispatcher.  All authority is worked out between the signalmen and the pilotman.

If this sounds confusing not to worry...British Rail put together an easy to understand training film on how single line working is to be carried out.  Just about the only sensible thing they do us to use both block instruments for the single track...shame they couldn't dream up a procedure to eliminate the 5 or so extra people involved.



If your eyes are spinning here is a bit of North American practice to take the edge off.  Here is video from Viaduct Junction in Cumberland, MD with Amtrak T30 getting some train orders hooped up followed by the operator copying down some train orders.



Ahhhh, modern efficiency.

TWC/ABS on the California Coast Line

So here is a little video example of how signaling works on a North American line with both Automatic Block and Track Warrant control.  Out west this is simply called TWC / ABS although in some parts of the east it is known as Rule 271.  Basically this is where block signals keep trains from colliding, but track warrants keep them from conflicting.  Previously trains would rely on the timetable and train order system to sort out who had priority on a single track main line, but since the advent of radio the dispatcher can just tell trains what he would like them to do directly.

Number plate? Check.  Hand throw switch? Check. Semaphore? Optional.

This line is the coastal route between San Francisco and Los Angeles comprising parts of the Coast and Santa Barbars subdivisions.  Because of the lack of through freight traffic the line has seen minimal investment from Union Pacific.  When recently the old pole line and searchlight signals were removed, UP declined to pony up for a CTC upgrade with its attendant interlockings and traffic control.  So while the signals are the typical type of LED Darth Vader with PTC antennas, crews must still copy down train orders and get out to hand throw switches for meets.

In this case upon leaving San Luis Obispo our train was issued a Track Warrant to a point called DEVON (which the crew insists on pronouncing incorrectly in the video).  Later we got another Track Warrant to proceed from DEVON to Santa Barbara, however the later would not enter into effect until we met a northbound UP freight train at DEVON and he took the siding (GCOR rulebook Box 5). 

The meeting point was well chosen as we arrived just as the opposing train was passing the automatic signal directly to the south which was indicating Approach.  Our train's conductor climbed down to the right of way and lined the hand throw switch for the freight train to save a little time, then returned it to the normal position so that we could proceed.  The fact that the freight train had more engines than cars indicates one of the reasons there has not been much investment in the line. 

Here's the thing.  While this is still all quaint and manual and worth filming as a quasi-historic railroad operating practice...without the pole line an searchlights this is basically just delaying my train with little value added. 

If you want to travel this line and check out the new old signaling there is a daily Coast Starlight round trip covering the TWC/ABS segments on both subdivisions as well as a Pacific Surfliner day trip option from Los Angeles to San Luis Obispo.

According to the Timetable - METRA Beverly Branch

While Timetable and Train Order operation isn't quite dead yet, the "timetable" part of it almost certainly is, even on the one line that officially still uses the system. This is because for all the talk of superior and inferior trains the LIRR does a pretty good job at making sure trains know explicitly when they have to take sidings due to the Manual Block system that covers the more traditional T&TO. Of course that is what I thought until I started going some research on METRA's Blue Island interlocking tower located on their Rock Island division.

Anyone familiarizing themselves with the METRA commuter network may have noticed the strange lack of any automatic signaling system on the Beverly Branch portion of the Rock Island District. The Beverly Branch is an interurban themed loop off the Rock Island main line that sees the majority of Rock Island district trains save for a few rush hour express runs. Running 6.5 miles from Gresham Junction to Blue Island – Vermont Street about 5 miles of that is not covered by any sort of automatic signaling, which under GCOR means ABS or CTC rules. Of course what the line lacks in signals it makes up for in stations with a total of 10 filling the unsignaled section between the new CP EZLIABETH and the 125th St interlocking.

Now unsignaled track, even on commuter rail lines isn't that uncommon, but if one reviews the operating rules for that section you will not see anything pertaining to Track Warrant Control or even its lesser known GCOR cousin Track Permit Control. What one finds instead is Time Spacing, which is defined in a serious of special instructions in the METRA employee timetable.

* A proceed indication displayed by the controlled signals governing entrance to the non-signaled territory or verbal authority from the train dispatcher or control operator will authorize trains which have scheduled passenger stops, as indicated in the Employee Train Schedule, to enter and run with the current of traffic in the non-signaled territory. A train must not follow another train until 10 minutes after the preceding train has departed.
* Road Dispatcher at Gresham Junction and Control Operator at Blue Island must hold trains at the controlled signals governing entrance to the non-signaled territory of the Beverly Sub District until 10 minutes after the preceding train has passed. They must also notify any train which is followed by a train scheduled to precede it.
* Trains not indicated in the Employee Train Schedule as operating via the Beverly Sub District and trains moving against the current of traffic will be authorized by track permit after an absolute block has been established in advance of the movement.

What we have here is a somewhat informal version of timetable operation which keeps the time separation components, but discards many of the issues about actually keeping to your assigned schedule. Only scheduled trains may enter the time separation area on signal indication, but it doesn't matter what that schedule is or if they are following it. The rationale behind this the high density of stations which all trains on the line must stop at. With stations less than one half mile apart each there isn’t much room for trains to build up a dangerous amount of speed and it is not difficult to observe any traffic running on the line ahead.

Even with the frequent station stops and a 30 mph maximum line speed, a second layer of safety is provided by the operators (now dispatcher in the case of Gresham) who cannot display a signal into the time separation without waiting 10 minutes since any preceding train was admitted. This time separation requirement applies for trains within the block which cannot depart a station any time sooner than 10 minutes after the preceding train has departed. The signals at both entrances to the section can either display some version of Clear and Restricting, so just like in manual block systems the Clear served as a manual block proceed indication that is valid all the way to the next interlocking, unless the train is held up by the at station 10 minute rule. At the new CP-ELIZEBETH (replacing a portion of the old Gresham Junction interlocking) you can see the proper direction track westbound signal can display G/R on the upper head and R/L on the lower. The reverse track can display G/R/L on the lower head.

While in theory time separation could be employed equally well on a bi-directional scheme with admittance to the blocks governed by the operators/dispatchers at either end, in practice all reverse direction moves must get a track warrant. Moreover all non-scheduled trains must also get a track warrant as no scheduled train skips any stops and the station stops serve as safety critical time checks.

Unfortunately all these stops come at the cost of timeliness with the 5 miles in the un-signaled territory taking upwards of 20 minutes to traverse according to the schedule. That means that the line would not do much worse if it was simply converted to Yard Limits and trains run at restricted speed (although you might not be able to make any stops). In terms of train frequency the shortest headways on this line are 13-14 minutes apart, although to handle the peak traffic other trains can be sent via the Main Line with its full CTC protection.

In advance of each exit interlocking, CP-ELIZABETH to the east and 125th St to the west, there is an automatic distant signal allowing the block in advance of exit interlocking to be run under ABS rules. The setup is reminiscent of Amtrak style Rule 562 operation with cab signals with fixed waysides only at distant.

The history behind why this stretch of line was left signaled the way it was is a bit of a mystery, especially considering that the Rock Island was the first to make use of RTA funds to improve its service. One probably culprit are the large number of grade crossings in the Beverly Hills section of the line with 24 being located in the unsignaled section. Automatic crossing protection using DC track circuits would have required complex logic when combined with automatic block signaling. Demands from the time to improve crossing protection or an effort by the Rock Island to avoid paying crossing tenders may have lead to the discontinuance of automatic signaling in that area. The practice may have also evolved from older manual block or timetable operation that was never upgraded due to the slow speeds and frequent station stops.

How much longer this practice will continue is a matter for speculation. The Rock Island district is already targeted for a pilot PTC system and such dark territory is the thing that PTC generally eliminates as part of required signaling upgrades. However PTC could be used as an overlay to provide actual enforcement of the current time separation and remove any necessity for track circuits on this stretch of track. The time separation rules would of course probably be left in place for when the PTC system inevitably doesn't work.

Rumors of Train Orders' Demise are Greatly Exaggerated

Last week it was reported that the Long Island Rail Road had "retired" its Train Order system inherited from the old PRR Standard Code rulebook.  The last Form 19 Train Order was issued on September 3rd at 11:59, removing the Form 19 from use as a train order device.  Prior to this the venerable Form 19 had only been used to deliver speed restrictions and other miscellaneous instructions with movement authorities being transferred to the new LIRR Form L.  While some had assumed this to mean that the LIRR was now using a modern Track Warrant system with paperwork similar to a NORAC Form D or MNRR Form M, the truth is that this only represented a change in paperwork.

The Form 19, seen below, was a long form train order where all the instructions were written out in long hand, on multiple copies and given to whomever it may concern.  The large block of text could confer a movement authority or seed restriction or just about anything safety related that a train needed to do.

The Form L on the other hand is broken up with those fill in the blank lines so common on track warrants and other movement permits in use across North America.  However while most of those other forms have 10 or more fill in the blank lines, the Form L only has 4, and none of them have anything to do with standard movement authority.  However there is a 5th block that contains a paragraph worth of blank lines for....hmmm...a long form, hand written block of instructions.

Upon inquiring I learned that there have been no alterations to LIRR operating practice except for the elimination of a Clearance Card C for passing a stop signal in favor of the Rule 241 verbal permission past a stop signal.  The LIRR still uses its traditional PRR manual block system with K cards, A cards and superior/inferior trains governed by timetable and, you guessed it, train orders.  So despite what you might hear, train order operation still lives on at America's oldest railroad.