Search This Blog

Thursday, February 28, 2019

LIRRs Insane Absolute Block Signals

Back in May I wrote a post covering the LIRR's new Reduced Aspect system.  Similar to Metro North's, the system uses some additional indications involving slow speeds as well as the color Lunar White to distinguish it from existing color light signals.  I was somewhat puzzled why, after adopting a new color light system to replace the older position light system, the LIRR would create a brand new system from scratch as opposed to just expanding, or using its color light system.  After all,  NORAC has had this down for years with the "Clear to Next Interlocking" modifier or the use of a Cab Speed signal with a Restricting option for failures.

In fact, I had heard that the LIRR had been using the "Flashing Green" aspect to indicate Absolute Block Clear.  It had never seen it, but it made sense.  Not to mention they had Manual Block Clear as an existing option as well.  A quick google search actually found a previously unknown LIRR signal rule reference.

NAME: Absolute-Clear.

INDICATION: Proceed; Track clear to next interlocking signal. Approach next interlocking signal prepared to stop.
Yeah, there you go.  If you want to go to color light, just use *G*/R. A nice uniform difference from NORAC Cab Speed.

Huh?  *G*/*R*?  That's a bit...odd.  I guess they really want to make it different from anything that might appear in the Amtrak zone?  Wait a minute...what's that in the text of Rule 298B?

Absolute Medium Clear?  Absolute Slow Clear? Oh no..

 NAME: Absolute-Medium-clear.

INDICATION: Proceed; Medium Speed within interlocking limits. Track clear to next interlocking signal. Approach next interlocking signal prepared to stop.

Are you kidding me?  This is the sort of think a child would come up with for their imagination railroad.  Oh wait, it gets crazier.

 NAME: Absolute Slow-clear.

INDICATION: Proceed; Slow speed within interlocking limits. Track clear to next interlocking signal. Approach next interlocking signal prepared to stop.

Yup, that is a flashing three headed signal. I mean I guess I see the logic.  The LIRR doesn't use flashing signals outside of the Amtrak zone so this associates flashing with an absolute block while not duplicating any existing signal aspects.

 NAME: Slow-approach

INDICATION: Proceed approaching next signal prepared to stop. Slow speed within interlocking limits

Ok, I guess that brakes the pattern.  Wait, on the PRR Slow Approach can stand in for Slow Clear on high signals.  What does the LIRR do there?

NAME: Flashing Slow-approach.

INDICATION: Train will proceed in accordance with signal indication within interlocking limits and after clearing the interlocking, proceed under absolute clear indication to the next interlocking.

They named a signal indication "Flashing Slow Approach".  I guess the other three signal rules used up all their creativity juice.  The fact that I only became aware of all this now just shows the extent to which the LIRR keeps its operating practices under wraps.  To be fair, this isn't as crazy as it appears.  Like I said, when this was developed in the 1970's the LIRR had avoided flashing signal aspects and also wanted to avoid conflicts with Amtrak zone signals (although there was and is no wayside-free operation in the Amtrak zone).  In the relay hut logic could use a single flashing circuit applied to the entire output of a signal when an Absolute Block signal was called for AND the system avoids the odd case of a "Clear to Next Interlocking" displayed along side an Approach signal, which can happen under NORAC despite being redundant.

This here is how you do absolute block.  End of discussion.

Ultimately it doesn't matter if the system makes sense when viewed at the right angle on a sunny day.  In a recent Newsday article, LIRR operating personnel were complaining that the new reduced aspect signals don't give the engineer enough warning, that train handling and/or the ability to maintain a schedule will suffer.  The Pennsylvania Railroad, the Long Island Rail Road's corporate parent until 1968, SOLVED this issue in the 1940's with the 'C' marker which simply modifies an existing signal aspect. The root of today's limited aspect problem is that in the 1970's, instead of adding one extra marker light and one extra signal rule, the LIRR decided to add 4 signal rules and 13(!) different indications to implement a cab signal system without fixed wayside signals and now trying to change it over to something like the NORAC method with color lights likely would lead to confusion. 😵

Metro-North started fresh in 1983 and first choose the PRR solution.
The rank and file of the LIRR have always prized a complex rulebook that is shrouded in secrecy in order to increase job security and overtime.  40 years later the management is now having to take drastic measures, beyond a simple color light conversion, to bring order to the chaos and unfortunately I suspect that all the old vestiges of the train order and manual block systems are likely to be next.

Thursday, February 21, 2019

Pneumatic Points Plan B - Engine Taps

I love pneumatic point machines. They are simple, powerful and they make cool noises. Created in a time when electricity and electric motors were complicated and expensive, the technology has not aged well as the cost of labour has skyrocketed past the cost of technology. Case in point is the old conundrum of what what one does if the air all runs out. While electric point machines have the equivalent disadvantage of not being able to function without electricity, they have been able to make up for this limitation through the widespread adoption of the dual control point machine. Downed power lines got you down? No problem! Just throw that big old lever by hand and watch the switch points move.

You see the rotational gear train of an electric drive is able to mesh with the rotation of a hand throw lever. Pneumatic points on the other hand use a linear piston and crank system. While there are certainly ways to incorporate a hand control, it would probably require a major redesign and add a significant amount of complexity.

So what does one do if your pneumatic interlocking plant literally runs out of gas? Well a little hint can be found on old PRR interlocking sheets. At various points on the diagram there are notes indicating the presence of an "engine tap". Once common, this device seems to have been mostly eliminated at surviving pneumatic interlockings and it took me until 2018 to actually encounter one in the wild at the Brilliant Branch wye switch at CP-HOME.

An engine tap is a valve on the interlocking air line with a standard railroad air brake coupling on the other end. In case air pressure drops below minimum operating levels, perhaps due to a compressor failure or power loss, locomotives were expected to connect their own air supply to the engine tap and pump up the plant's air reservoir using the locomotive's own air system. In fact, while reading an old PRR book I remember a story about how during the Northeast blackout of 1965, the first engine movement authorized in the Philadelphia area was for a pair of diesel road freights to run lite to ZOO interlocking in order to connect to the air system and keep the interlocking plant operational.

Why were these useful devices removed? Well I have to assume that electric power and automatic air compressor became more reliable. There is also the risk of vandalism/sabotage if random people are able to simply vent an interlocking's air system to the atmosphere (recall that engine taps were usually included at manned interlockings with vigilant operators). Without the engine tap railroads reverted to a Plan C, which boiled down to having maintainers remove the cover, hand crank the points to the desired position (if necessary) and then spike and wedge the points until air power could be restored. Evidence of spike and wedge operation was in evidence at the Pensy high point CP-AR where each pneumatic point machine was provided with a brightly painted wooden wedge and matching railroad spikes.

 With pneumatic point machines rapidly vanishing it won't be long until the only place this sort of thing applies is Penn Station New York and Washington Union Terminal, and those places probably already have all sorts of more conventional redundancies.

Tuesday, February 12, 2019

Last Call At Tipton and Fostoria

Some railfan locations need no more description than a single word.  For decades the 3-track PRR signal bridges at Tipton, PA and Fostoria, PA had provided such an exciting backdrop that one is pretty much guarenteed to find a railfan at one of those locations "on duty" from sun up until about midnight because hey, night photos :-)  Anyway the creeping re-signaling effort is getting closer to these iconic locations, so close that the new blue SIP signs have been placed on the relay huts with a bit of the black plastic on top.  Therefore it is probably your last chance to get out and get some photos at these locations before they are rendered completely worthless.  Remember, there won't just be some new modern type of signal, there won't be any at all.

Tuesday, February 5, 2019

Signs! Signs! Everywhere a Sign! - Eastern Passenger Roads

In Part 1 of my look at railroad station signs I covered the East Of Mississippi Class 1 freight railroads, NS, CSX, CP, etc.  Here in Part 2 I am going to be covering the passenger roads in the northeast, Amtrak, SEPTA, NJT, LIRR, Metro North, etc.  Surprisingly, as time has gone on the passenger roads have become significantly less labeled than their freight counterparts.  This could be due to cost cutting, a compact territory that makes getting lost less likely or simply a desire to hide operating practices from the general public. 

Amtrak operates its own trackage as part of the Northeast Corridor, Springfield Line, Harrisburg Line and, for a time, the Atlantic City Line.  Inheriting the infrastructure from bankrupt roads that would be later folded into Conrail, Amtrak would often just leave the old, typically Penn Central, sign in place.

The first thing Amtrak decided to properly brand were its manned interlocking towers where they
adopted a white on blue motif that would last through the present day. 

For remote interlockings constructed during the early NEC Improvement Project era, the Government dollars didn't really cover signs so Amtrak had to settle for stenciling on the relay hut.

The next standard that appeared around 1990 was a totally-not-Conrail white letters on blue background sign which also appeared on the Atlantic City and Springfield lines that were re-signaled at that time.

In the late 1990's Amtrak decided to add a touch of flare with a colorful sign that really showed off the old pointless arrow logo.  These appeared in just a few locations.

Meanwhile, further north Amtrak experimented with a white on black sign.  These are mostly seen on the Boston to New Haven segment and in northern New Jersey.

Which leads us to the present standard which I would call "low observable".  Not sure why Amtrak doesn't want to advertise it's interlocking names, but at least they kept the white on blue.