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| PHOTOS: ALTO TOWER (917923) | |||
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PHOTOS: ALTO TOWER |
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Posted by Jersey Mike on Sun Mar 28 15:08:19 2010 Seeing as how my 2009 PRR Main Line Survey has reached the Golden City of the PRR I thought it appropriate to reach back into my archives and post some photos on the famous PRR interlocking that still routes trains around the large yard and shop complex 24/7 as it has for the past 100 years.I am talking about ALTO tower and about 5 years ago I took a little trip there when Amtrak still ran two round trips a day on the main line and it was possible to get out and back in the same day. Now I am sure I posted the photos from this trip up on Subchat so if you remember that you might be wondering why I am replaying photos from 5 years ago, its because at the time I was not at liberty to post all of the pictures I took. You see I was able to not only take pictures of ALTO tower, but also inside ALTO tower and after sort of forgetting about them for a while I realized it was safe to post them up on Subchat. Anyway, ALTO was built around 1910 in the typical PRR style of all-wooden main line towers with the trademark bay windows. Over the years CTC control of the entire Altoona terminal area was transfered to ALTO and in the 1970's the interlocking was somewhat rebuilt by the Penn Central. Because of the CTC ALTO has survives as an active interlocking tower and currently controls ANTIS, HOMER, ROSE, WORKS and SLOPE interlockings. So here is ALTO tower from the front. It had been last painted in Conrail colors in the 1980's and at this point is looking somewhat shabby. In 2009 NS came by and provided a nice re-paint job in an overall flat gray.  ALTO from the side showing the side bay extension that was added because of the need for a longer interlocking machine inside. Access to the tower is across the tracks, not from the road behind.  From this rear view you can see a newer steel external stairway, fuel tank for either the heater or emergency generator and the old style relay cabinets for the signal gantry.  It's amazing some of the architectural details that went into these old towers.  ALTO interlocking is made up from two logical parts. There is the main interlocking controlled from the original interlocking machine, and a smaller extension controlled from a partially independent machine next to it. The PRR pedestal signals at the west end of the Altoona station platform are part of the extension, while the large signal bridge controls access into the interlocking proper. Here an Amtrak train waits to depart Altoona station on a Medium Clear aspect on the 38L pedestal signal for a diverging movement from 2tk to 3tk, while the 2L signal on the main bridge displays Clear. This is the point where #3 track begins and will remain until CP-CONPIT. Also in this picture we see a pair of helpers waiting in the pocket and an eastbound freight train about to roll through on #1 track.  Closeup of the 38L signal displaying Medium Clear.  The famous ALTO signal gantry was installed during the Penn Central era. It holds the 2L, 6L and 8L signals.  ALTO tower is designed to facilitate helper movements and has a pocket track between 1 and 2 tracks that allow helpers to latch onto passing main line trains. Here a helper pair lay over in the pocket tack under the famous gantry.  The eastbound gantry is a very early design that really skimps on the raw materials, which were much more expensive back in the day. This gantry supports signals for #1 track and #0 track. In the foreground is the tower operator's car.  Rear view of the 10R and 12R signals on the old gantry. SLOPE interlocking can be seen far in the background.  Moving inside the tower we find a very early model US&S Electro-Pneumatic machine. This offering predates any concept of Model so it is only known as an Electro-Pneumatic machine. The Pneumatic comes from the pneumatically powered points and not anything inside the interlocking itself. Here we see levers 1 through 13. Odd are for points and even are for signals. Signal levers mostly have two positions to control a pair of signals, although at some point a few, like 4R, only have one. The lamps light either when a lever is free to be moved or is locked.  The east end extension is slightly newer and holds levers 31 through 38.  The Model Board was modernized sometime during the Conrail era with a plastic front, miniaturized lamps and label maker labels. This is the east end showing the two main tracks, a controlled siding and a yard lead. The blue lamps on the arrows are traffic control indications. Traffic control is handled from the CTC machine. Also note that a turnout from 1tk to 2tk allowing access to 3tk has been removed in recent times due to the lack of need for a parallel ladder.  Center right portion of the model board. Some signals are marked "phantom". This means the signals are there logically, but not there in reality. This is an artifact of the second interlocking machine installed for the east end extension.  Central part of the model board showing the two signal gantries and ALTO tower. Here is the main trailing ladder track used by trains going to/from the yard and helpers.  Left side of the model board showing the extension of the ladder on #3 and #2 tracks.  Some of the signal rundown timers, cleaning supplies, blocking devices and in the background you can see the SLOPE interlocking CTC machine.  SLOPE was the first interlocking remoted to ALTO and is only about a half mile to the west. SLOPE terminates the '0' track and also provides a facing point crossover from #1 track to #2 track, an option that is not present in ALTO proper. The interlocking is controlled from a simple CTC toggle board and I assume it uses pulse code control used in the cabinet below.  Operator's desk showing the computer which tells him or her what trains are approaching. Also there is still a paper block sheet which needs to be filled out. This tower used to report trains to 'C' tower, but its closure removed that requirement. To the operator's left is the CTC console that controls the rest of the Altoona terminal.  Here is the east half of the CTC console showing ANTIS, HOMER and ROSE interlockings.  West side of the CTC machine showing HOMER, ROSE and WORKS interlocking.  Rear of the interlocking machine, lockers and doorway.  Rear of the interlocking machine and model board.  ALTO as seen from itself, with a train passing by.  Coal train making a diverging(?) move from 2tk to 2tk.  Anyway hope you enjoyed that and PLEASE leave comments on my PRR Main Line survey. Each part takes like 2 hours to write up. |
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