The Other Rule G

The evolution from "Stop and Proceed" to "Restricted Proceed" in North America is long and something I hope to tackle at a later date. A holdover from the timetable and train order era where waiting for a train running ahead increase its lead made some sense to reduce collisions, the fuel and time savings of allowing following movements to keep moving is hard to deny.  However even where Stop and Proceed are the norm, exceptions are necessary where something like a stiff grade might make restarting a heavy freight train difficult. To implement these exceptions, the (G) or Grade marker was used on automatic signals to relieve some or all trains of the need to stop when paired with a Stop and Proceed indication.

Stop and Proceed was especially popular in the Northeast United States, but after Conrail was picked apart by NS and CSX, most of the major northeastern freight territory fell under the spell of Restricted Proceed.  At this point the G marker appeared to be on its way out as the remaining NORAC roads were either passenger focused or too small to have signals or heavy freight trains. However, as the limited speed triangle, Amtrak's Harrisburg line turned into an unwitting refuge. The PRR's Main Line between Philadelphia and Harrisburg was surprisingly hilly and saw more than its fair share of automatic signals with (G) markers applied.

One might assume that the spread of Rule 562 cab signals without intermediate wayside signals and complete lack of through freight would put the Main Line's (G) markers into a terminal decline, however at the Milepost 21 intermediate signal, a minor capacity project may have what could be the last new main line (G) marker to be installed in the United States. 

When Amtrak wanted to upgrade the single direction tracks tracks between the SEPTA Yard at Frazer and the start of 4-track operation at Paoli, they modified Milepost 21 intermediate signal location for bi-directional operation on both tracks with new Safetran colorized position lights and (G) markers in the eastbound direction.  Moreover, the (G) even uses the same old school blocky font as opposed to the smoother letter used on things like (D)istant and (A)pproach markers.

It's anyone's guess how much longer these (G) markers will be around for as the track segment they govern will soon be subjected to the Rule 562 treatment. Another part of Amtrak territory south of Wilmington also features both long freight trains and (G) markers, but it too going the 562 route so its a good chance that these will be the last new (G)'s installed in the United States. 

Small Changes at Western Ave

While out visiting METRA TOWER A-2 at Chicago's Western Ave for the first time in many years, I noticed that the US&S H-2 dwarf searchlight signals at the adjacent TOWER A-3 interlocking had been replaced by L&W LED searchlights with a small backing target. It is unclear if this took place in conjunction with the 2019 removal of legacy PRR position lights at TOWER A-2. TOWER A-3 is remote from a panel inside the staffed TOWER A-2 and the interlocking's other distinctive features including gantry mounted main line searchlights and A-5 pneumatic point machines had been left untouched. You can see the difference between the old H-2 searchlights and newer LED dwarfs below.

  


An interesting feature is that the 6L dwarf appears to illuminate only with a route is lines (or I assume upon the occupation of adjacent track circuits). This signal is placed after a train exits the main line, but before it is routed to a yard track. I managed to catch the 6L LED dwarf displaying a flashing red "Restricted Proceed" indication for a yard move, in conjunction with a lunar white Restricting aspect on the 10L gantry signal. (Note the 10L signal displays "3rd head Restricting" with a phantom center head.)



I assume that the H-2 yard dwarfs always displayed R stop or L Restricting and the LED units changed this to *R* Restricted Proceed as is the style today. I guess its cheaper to have an LED unit with just a single color of LED's, but I will point out that Union Pacific did choose to use lunar LED searchlights at the nearby KEDZIE interlocking.

Tight Jeans: Position Lights As The PRR Intended

We all know the PRR Position Light signal looks like this with the round upper head and the (usually) squared off lower head. Both backing targets are technically interchangeable with each other (Although I have never seen a lower head type target used on an upper head.). 

However what would you think if I told you that this concept of the PRR PL did not reflect the original vision of the author. A while ago I wrote up a post discussing the compact position light and how the lamp arms of a US&S pattern position light can support a PL lamp module at any point along their length.  At the time I thought that there were two standard PL setups, full size and compact. Well it turns out there is a third method of lamp arrangement which was actually the standard setup used by the PRR in its final few decades. 

While the PRR was an industrial behemoth that didn't hesitate to spend on quality, there were a few areas where its famed standardization turned more towards penny pinching. One of these was the configuration for the lower heads of its position light signals. To make the signals stand out in bright sun, a dark backing target would be necessary. However there would be little need for this contrast if an approaching train was moving at slow speed below 30mph. Therefore the PRR only applied a backing to the lower | position as the lower / and \ positions would be approached at something more like 15mph. 

If you look closely at one of these original pattern lower heads you'll also see that the modules for the / and \ positions are not positioned at the ends of the mounting arms. Instead they are scrunched in couple inches. Although not to the level seen in compact PL arrangements, this scrunch may have been to provide some contrast without the "expense" of a backing plate. 

See the difference between the placement of the lamps on the | vs the \ position.

I am sure the rivet counting modelers are yelling at their screens right now about my obliviousness, but somehow I had never noticed this before. I guess this is partly because unmodified PRR position lights have become so uncommon, but also because later lower backing plate thoroughly set the expectation that the spacing would be the same on both heads. Anyway now I know and now you know as well.

Hoboken Terminal's Suspended Signals

Stations with large terminal fans often exhibit a problem at one or both of edge tracks. Because rail vehicles can't generally make hard right turns, one needs a longer series of switches to reach the highest and/or lowest track. Unfortunately terminals often abut a fixed location like a river or street or public square and to avoid having those extreme tracks things can get a little squished. In the early 1980s, New Jersey Transit engaged in a near total reconstruction of the former Delaware, Lackawanna and Western electrified suburban network. Not only was the 3kv DC traction power system under powered and on its last legs, but the signaling system was firmly rooted in the 1920's. In the re-signaling project that followed, NJT built the last great North American interlocking tower, TERMINAL TOWER and replaced most vestiges of the former DL&W plant.

New (frame left) and old HOBOKEN TERMINAL TOWERs shortly before cutover.

In the late DL&W era Hoboken Terminal signals consisted largely of two head, small target searchlight signals displaying the DL&W's unique mix of color light signal indications. Long platforms in the center of the terminal had these mounted on signal gantries in the normal way, while tracks towards the edge of the low 1908 train shed saw signals mounted below the gantries under the shed itself. Moreover, while center tracks could get a "straight" clear out of town, tracks towards the edges had to make do with a Restricting indication as the DL&W lacked Slow Clear and Slow Approach options, even on dwarfs. 

When NJT rebuilt the signaling there appears to be a time when the new signals were wired into the old HOBOKEN TERMINAL tower's old US&S 1908 Electro-Pneumatic interlocking machine. To make the cutover process easier, signal locations were largely kept the same, but NJT had no desire to keep the old handicap of trains of edge tracks departing under a Restricting signal indication. This meant that the replacement "high" signals had to display R/R/G Slow Clear as opposed to the G and G/G on a dwarf. In most locations this wasn't a big deal as the signal gantries could easily support three tri-light heads, however on tracks 2, 3, 12 and 13, the need to suspend signals under the trainshed due to the closeness of the first switches presented a bit of a problem.

TERMINAL TOWER 36W2 and 36W1 suspended signals governing tracks 3 and 2 respectively.

TERMINAL TOWER 88W and 92W suspended signals governing tracks 13 and 12 respectively.

The solution was somewhat akin to a Penn Station signal, just with three "heads" instead of two. To display R/R/G, R/R/*Y* and R/R/Y, two fixed Safetran modular dwarf cubes were mounted close above an additional three-unit cluster of modular dwarf cubes. These were then mounted close under the roof at the westernmost end of the trainshed.

36W2 signal governing track #3.

 

Although a bit inelegant compared to a dwarf or today's compact LED searchlights, they are a unique solution in today's largely homogeneous signaling environment and are likely to persist for many years to come.