Portland MAX Signaling Primer

In the 1980's and 90's North America's light rail renaissance didn't just save money over traditional urban metro systems by embracing street running and low level boarding. At the time, the signaling standard for "heavy" metros involved full CTC and cab signaled ATC, which came with both high infrastructural and operational costs. However light rail systems got a pass to re-write the rule book and adopt signaling practices that hankered back to the low cost interurbans of old with single direction operation and limited use of interlockings. While I have previously covered two examples of these low cost signaling practices in Denver and Dallas, I recently had the chance to explore a third in Portland Oregon.

Beginning operations in 1988 and seeing significant expansion in the 90's and 2000's, Portland's MAX light rail has the typical mix of downtown street running and dedicated suburban rights of way with operating speeds up to 55mph. The signaling of choice is single direction 3-aspect Automatic Block signaling using US&S transit type signal heads. There is little formal distinction between interlocking and intermediate signals each signal is the same in having a line-prefixed number plate.

One quirk of the system is the setup of having an ABS exit signal at each station and another ABS signal between stations. When a station platform s within a block, the signal will at best display yellow Approach so there is a distinct rhythm of exiting a platform on a Clear then entering the next on Approach. Intermediate signals on the main line away from stations are often of the high mast variety with earlier installations using US&S N type mono-block heads.

A key feature of the MAX train control system is the use of fixed inductive Automatic Train Stop (ATS). Unlike some other systems, MAX actually includes a bit of overlap to get trains stopped before they hit something. This is made possible by an LRV's enhanced braking performance necessary to handle the challenges of street running. Apparently MAX also has a few ATS based speed control timers that function independently of fixed signals, but are indicated by wayside signs.

Interlockings are limited to major junctions, yards and a few select crossovers. These are supplemented by hand operated temporary block stations. As I said before, both ABS and Interlocking signals are largely the same except for the possibility for route indications on the interlocking signals. This can range from the use of a single lamp in the "call-on" position, or separate heads, each governing a specific route. The wayside signals are supplemented by switch position indicators of the US&S ES-20 variety.

When Urbex Meets Signaling

While there is a lot of crossover between the urban exploration (Urbex) community and the rail enthusiast community, the Ven diagram doesn't quite work the way you think it does as there is both the type of enthusiasm the individual is involves with (rail, urbex or both) and the type of things they explore.  When railfans explore rail stuff, they tend to put the resulting content in the rail bin, even if they are also into Urbex.  Qualified railfans know the jargon and historical details to properly label their content, rendering it searchable and discoverable. On the other hand, Urbex people who aren't railfans, can get into a lot of interesting rail places, yet have little idea of what they are looking at, therefore harming discovery.

Not so long ago I found some critical WINSLOW tower interior photos from 2003 on an urbex blog site that just hadn't happened to appear on casual google searches until recently. In the same vein, I also found a great exploration of the former PRR MG tower on the famous East Slope between the Horseshoe Curve and the summit at Gallitzin. I routinely search for new "interlocking tower" videos, but not "switch tower" because the genericness of the term returns a lot of bad results.  It was only after several years would YouTube searches include this video in my interlocking tower search due to the key words in the comments.

Despite their lack of historical context, the Urbex community can assist the railfan community by being willing to generally take more risks than railfans. In this example MG tower is known to see increased police patrols to the point where the risk of visiting is well known.  On the other hand, Urbex folk don't care about getting train photos and can put more effort into not being see in addition to just having more experience in not being seen. Therefore, while railfans steered clear of MG, this guy was able to made a comprehensive video documentation. Another popular urbex assist has been the Hoosac Tunnel in northwestern Massachusetts, which sees both explorers and ghost-hunters occasionally getting some footage of the searchlight signals inside.   

Anyway, the next time you are looking for some open source intelligence on some hard to access signaling artifact, try to use some urbex search terms. You might find something surprising.

New Signals at Portland Union Station

For the last year or more, Portland (Oregon) Union Station has been involved in a slow motion re-signaling project that will unfortunately zap the last active vestiges of VC Tower, which closed in 1996 as Oregon's last active interlocking station. 

Until labor dynamic forced a change in the early 2000's it was not uncommon for railroads to splice old interlocking hardware, like switches and signals, into new control logic. VC was one such example where the eastbound signals were left untouched. 

These included a short mast signal off of passenger track #1 with a mix of GRS type E and L&W modular lamps, a modernized GRS type MF triangular dwarf, (popular with UP in the 80's and 90's) off main track #4 and two vintage GRS type MD dwarfs on track #3 and #5 that likely date back to whenever VC tower changed over from semaphore signals. 

The replacement will be an obtrusive double cantilever mast for tracks 3, 4 and 5 and a likely modern type mast on track #1. 

The current two lamp dwarf signals appear to consist of a red lamp over a yellow lamp, which would provide for Y Approach, R/Y Diverging Approach and *R* Restricting, although was not able to observe actual operations. The new signals seem to bring Y/Y Approach Diverging to the table. 

The changes aren't limited to the east side of the terminal. For some time passenger tracks 1 through 4 have been un-signaled with the west end of of those tracks being reached via non-interlocked M23 powered switches. Based on bagged station track signals and a bagged through track mast it appears the west end will also be interlocked, including the presently hand throw station track #1.

This will hopefully cut a couple of minutes off the run time, with trains possibly able to make hotter stops, instead of creeping down the super long platforms. 

The End of Main Line Pneumatic Points

There's a lot of work taking place on the former PRR Northeast Corridor these days and unfortunately it appears that the era of main line pneumatic point machines might be nearing an end. The stock of pneumatic interlockings had been dwindling for years with LANDOVER near Washington, DC, GRUNDY in Bristol, PA and FAIR in Trenton being the two latest to see wholesale conversion to electric US&S M3 style machines. Prior to that both THORN and PAOLI interlockings on the Harrisburg Line saw their pneumatics go even while their interlocking towers remained open.

Currently, what had been some of the best preserved main line pneumatic interlocking plants, RIVER and POINT at the north end of Baltimore's Bayview yard, are in the midst of an electric conversion as their turnouts are being replaced as part of a general maintenance project. 

Unfortunately, due to their location, these two locations are difficult to photograph except from the rear of passing Amfleet equipped trains.

This will leave what is in my estimation only a single intact pneumatic main line  interlocking plant, HOLMES, at Homesburg Jct in Philadelphia. OVERBROOK interlocking, with its staffed tower, is still largely pneumatic, but had seen select turnouts replaced with M3's.

 

Of course a significant number of terminal plants will remain pneumatic for the foreseeable future and one could possibly count terminal adjacent interlockings like Metra's TOWER A-2 and SEPTA's 16TH ST as Main Line as well, however neither see the high speed movements currently present at RIVER, POINT and HOLMES. The challenge for documentation is capturing the movement and sounds of the switches as they throw. At HOLMES this is most easily covered when local freights enter and exit the Buttleton branch, but this could also be achieved when tracks are out of service east or west of the plant.  Of course the easiest way to engage with pneumatic point machines is to see them on rapid transit systems such as The PATH, NYC Subway and the SEPTA Broad Street Line.

US&S Loses Its Home Field Advantage

 Union Switch and Signal had always maintained a bit of a home field advantage around Pittsburgh, with the local railroads, most notably the PRR, preferring their products. As railroads grew larger, this hold field advantage grew smaller, mostly applying to the home town Port Authority Transit light rail Union Railroad. For example, both were some of the few customers of US&S's 80's pattern modular signals that were attempting to compete with Safetran's scallop shells.

Well, it appears that since the purchases by Ansaldo and more recently, Hitatchi, US&S has lost its local influence and the Union Railroad is now installing L&W brand signals from Missouri.

The URR was always a bit of a potpourri of signals, but the 80's US&S modular fare always stood out.

Arizona's Sky Island SP Signals Vanish

In southern Arizona one encounters the phenomena known as sky islands, where isolated mountain ranges, separated by harsh desert, become in effect islands for various plant and animal species due to the cooler temperatures and relative abundance of water. The Dragoon Mountains were one of these ecological islands that also happened to host an island of late model Southern Pacific signaling with short stature modular target signals. They had even survived the PTC asteroid with the familiar antennas installed to their original relay cabinets. This island was located on the double track section between VAIL XOVERS at Milepost 1000 and Dragoon Road at Milepost 1053. You can therefore imagine my dismay when I was passing the Sybil Road crossing at Milepost 1041.8 and saw a set of new Union Pacific LED signal masts.

Sybil Road 2016

Sybil Road 2024

The re-signaling took place between 2020 and the end of 2021. I suspect that Phoenix became so hot that the signal crews migrated to the cooler 4000 foot elevation of the Dragoon pass. In fact the riding temperatures of the southwest may have played a factor in shifting the signal locations nearer to road crossings. The Southern Pacific Milepost 1041 intermediates were actually a half mile to the west.

Sorry again for a late report, I just hadn't realized what had been lost until I was physically on site. The signal relocations and approach lighting so make the new signals more useful for railfanning train movements, however quite has been lost regarding the actual photo composition.

Inside WINSLOW Tower: Then and Now

If there was a moment where I got into railroad signaling, it would be in the fall of 1998 when I quite literally got "into" railroad signaling. While being dropped off at South Jersey's Winslow Jct for the purpose of completing a 20 mile hike for a Boy Scout merit badge requirement, I noticed that one of the omnipresent plywood panels securing the lower level of WINSLOW tower had been removed. Scrambling inside I was presented with a trove of wonders that forever whet my appetite for the age of relay technology. I luckily had a 35mm film camera with me and was able to take a few photographs, but with my plan for the day already set, I only had about 10 minutes to get my fill. Although I had the motivation and opportunity to return, I as busy with school and kid stuff and by whatever time I did go back the tower had been re-secured. 

For the next two decades I would periodically check up on the tower, waiting for locals to break back in so I could follow up with more photos. It was only in 2023 that I was provided with a do over and lets just say, things were quite different. While I've covered South Jersey's WINSLOW tower and the ghostly remains of the interlocking plant on this blog before, today we will explore the interior with two groups of my own photos photos taken 25 years apart, with some additional insights provided from a 2003 urbex visit and photos from when the tower was still in service. 

If you are not familiar with WINSLOW (aka WINSLOW JCT), please check out my previous coverage to get a better idea of its history and layout. to summarize, WINSLOW was built in 1934 as part of the Pennsylvania-Reading Seashore Lines merger to PRR specifications with a brick tower, bay window and a US&S Model 14 electro-pneumatic interlocking plant. The tower was in service until 1983 when the NJDoT seashore services, run under contract by Conrail, were discontinued due to lower ridership and rapidly declining track conditions. The final service level consisted of 3 peak direction round trips to Atlantic City and 1-2 round trips to Ocean City and Cape May. When the tower closed the signals were turned and remained in place until Amtrak showed up to rebuild the line about 5 years later. 

When I first got into WINSLOW it was about a decade into its second act as a radio repeater base for NJT operations on the line. A small lattice radio mast had been build against the north side of the tower and the upper story windows were still intact and letting in light. Towers serving in useful capacities as relay huts or crew bases is one of the more common factors behind their not getting demolished. 

 
On the ground floor, the relay racks and associated relays had been removed, however the cabling that fed the US&S Model 14 interlocking machine on the operator's floor was largely still in place. From the look of it, one can see why so many old tower had their own regular maintainer that under the old system of inefficient railroad employment, could be in the position for many years.

When I visited in 1998 I don't remember much of anything in the ground floor, but in the 2003 urbex photo we can see that it was being used for general storage. I recall being informed by a Southern Railway of NJ employee mentioned that they had access to the tower, but I can't confirm if the items being stored were theirs or not.

There is a single flight of stairs along the rear wall connecting the relay room to the operator's floor. I could not tell if the relays were caged off or not as this was the typical practice to prevent operators from being tempted to tamper with the interlocking equipment to "fix" certain problems. In the 2003 photos we can see shelf style relays on the stairs, but I did not recall seeing any in 1998.

Heading up the single flight of stairs to the operator's level revealed something unexpected, a false wall built lengthwise across the room with a door in it. 

The false wall had the unfortunate effect of blocking the view of the original PRR pattern model board, expect for a small bit at the top. I also managed to get a tight angle photo in from the side that came out pretty well all things considered. 

The model board matches its final appearance from the mid-1960's through to 1983 where the main lines to Atlantic and Ocean cities were both single track manual block. 

What really blew my mind back in the day was the presence of WINSLOW's 27 lever US&S Model 14 interlocking machine. Until this point I had never physically seen one or even known what one was. While some of my railroad books had contained pictures of specifically PRSL Model 14's, the fact that they didn't look like the classic armstrong type lever frame made it hard to intuit what that strange box thing in the photo was until I literally stumbled upon one and it all clicked, despite the lever cranks had all been removed.

Here is the WINSLOW machine as it appeared in service.