18-05-25 PHOTOS: AR UN

The high point of a mountain railroad has historically been a very busy place often with sidings and loop tracks that enable helpers to uncouple on the fly and then head back down the mountain to help another train ascend. At the PRR's high point, she summit tunnels at Gallitzin, PA, 2173 feet above sea level, is typically where all the photos are taken, however the real guts of the operation are about a half mile to the west where the dual interlockings of AR and UN are located. Connected by a loop track dating from the days of steam and manually controlled from an interlocking tower until 1994, the AR-UN complex still seems a bit frozen in time, with position lights and pneumatic point machines, although both are now slated for replacement.

I was able to visit the AR-UN complex as part of a Memorial Day road trip to Clarion, PA. The trip also involved a stop at CP-GRAY and the automatic signals at Tipton, completing my documentation efforts started back in the previous December, at those two locations. Also included in this 800 photo set are some summertime photos of the Tunnel-Bridge-Tunnel complex on the former L&MS Western Pennsylvania Main Line at Clarion.

AR (Allegheny Ridge) tower is located along the current eastbound Track #1 about a half a mile west of the New Portage tunnel that was originally built for the Pennsylvania canal system. Currently only the center track #2 is signaled for bi-directional operation, but the full mast signal being installed indicates that Rule 261 will be coming to all three tracks. The 4 main tracks west of CP-AR narrow to a single track via an equilateral switch so that doublestacks and other dimensional loads can fit through the tunnel. Up into the Conrail era this route would accommodate two tracks through the tunnel.

The World War 2 vintage AR tower actually consolidated the work of 4 previous towers into one modern brick structure. In addition to AR interlocking it also handled UN interlockings covering tracks 2 and 3 (formerly tracks 3 and 4) on the other side of the loop, SF interlocking east of the tunnels at the junction of the Muleshoe Curve route and BF interlocking, providing crossovers further east of SF. AR tower was built with a flat roof, but was retrofitted with an angled roof in the Conrail era to prevent leaks. The outbuilding used to house the compressor plant for the pneumatic switches and currently supports 100hz signal power generation. The tower was closed in 1994 along with MG, MO and SO as part of a Conrail re-signaling effort.

The eastbound signal bridge governs traffic on Tracks 0, 1 and 2 along with a dump siding. Although there are 3 designated main tracks, 0 is in essence a siding that runs just 2 miles between CP-MO and CP-AR. This incarnation of Track #2 also only runs between CP-MO and CP-AR and forces what are normally tracks 2 and 3 to number++ between CP-UN and CP-MO. A clear signal is being displayed for the next eastbound train on main track #1. Also note that the signals for both tracks #1 and #2 can display a Clear indication over the equilateral turnout. The new 4-track signal bridge won't change much, except the low speed turnouts off 0 and the dump siding will have high color light signals that can both display Slow Clear. 

AR tower as seen from the west with the #1 switch in the foreground.

Rear view of AR tower showing the old compressor house and a vintage pole line pole that has been left standing.

Possibly as a wartime economy measure, AR tower was fitted with 2 smaller US&S Model 14 interlocking machines, instead of one large one. The near machine, #2, worked SF and BF interlockings while machine #1 handled AR and UN.

The Model 14's were largely intact and open for inspection, just like the big on at the HARRIS tower museum. Unfortunately their condition was much more rusty :-\

 New and old signals for trains heading off the loop track and back down the east slope to Altoona.

With most helpers being cut off on the Main Line closer to Pittsburgh, the Altoona loop track was being used to store MoW vehicles.

The only train that passed by had the standard pair of SD40E (rebuilt SD50s #6304 and #6317) helpers on the end, seen here rolling past CP-UN
 

I had better luck at CP-GRAY where I caught SD70M-2 #2666 and C44-9W #9447 at the head of a westbound stack train.

Along with NS ES44AC #8145 and endangered standard cab SD70 #2566!

I talked about the Clarion Trestle complex back around New Years, however long story short it was an effort by the Lake Shore and Michigan Southern arm of the New York Central to access the western PA coal region with a "modern" double track main line. Of course modern meant 1920's and 1920's means whatever one was building would go unfinished when the Great Depression hit. Never operated as anything more than a secondary track, the Western PA branch was eventually abandoned. Today the tunnels develop neat fog effects on humid summer days.

Westbound view of the trestle showing the unfinished second trackbed.

Views of the Clarion river to the north and south.

Without the snow and ice I felt comfortable crossing the gap in the middle and continued on to the west side of the bridge.

The western tunnel showing it's own bit of mist.

Eastward view of the trestle showing one of the futile efforts of local authorities to keep people off.

Western end of the east tunnel.

On a muggy day like this I headed by to my host's house for a rail themed beverage. I wonder if the company will end up merged with the roughly similar Lackawanna Brewing company.

While killing time I noticed that many of the elements supporting a local natural gas field resembled the kit needed to support a pneumatic interlocking.

The Piney Dam was built on the Clarion River in 1924 and produces 30MW of electrical power.

I'll sign off with this photo of the Tipton signal bridge at Milepost 225 on the PRR Main Line. Just minutes off I-99, this railfan location will likely fade into history after the position lights are removed.

Well that's it for now. Tune in next week for something historic.