In today's episode we will take a look inside PAOLI tower via a series of photos that were taken in 2004. As far as I am aware there have been few changes to the tower since then so as of 2010 this information should still be valid. PAOLI Tower was built in 1896 with a mechanical frame and shared design elements with adjacent BRYN MAWR tower and CLY tower a bit further away on the banks of the Susquehanna River. PAOLI was an intermediate design between the generation of all wood towers and the later PRR standard all-brick towers. It literally split the difference with a brick base and a wooden upper story.
PAOLI tower is showing its age with a large brick patch on on its lower level and a large piece of plywood blocking off the location of its bay window that probably succumbed to rot or some such. PAOLI is also suffering from Tower Window Syndrome and as built was fully surrounded by full length double hung windows that have since been boarded over or replaced with modern window types. The tower retained its classic look through the 1960's, but at some point thereafter suffered the blows to its appearance. PAOLI's original PRR style nameplate was later replaced by a more dynamic Penn Central green nameplate and ultimately a plain blue Amtrak nameplate which about 25 years later is heavily faded.
Here in 2004 we can see that in the intervening 6 years the tower has seen a bit of work on its tin roof with a coat of heat reducing silver paint being applied. In this image you can better see the roof patch where the bay hip roof merged with the main roof. I really don't know the story behind that large brick patch, but I am assuming that something crashed into the tower back in a day when such damage was still deemed worthy of repair.
Here we see the east side and wear of the tower. A fenced in employee parking area is located directly behind the tower for the operator and any signal maintainers.
Here is a direct rear view of the tower showing the horizontal symmetry about the chimney as well as the fuel oil tank.
Side view showing the operator's entrance. The west side of the tower had the door for the maintainer's entrance. There is no internal connection between the lever room and locking room.
The internal stairway to the lever room showing 115 years of wear.
At the top of the stairs one encounters the big double length 1930's pattern US&S Model 14 interlocking machine with the model board straddling the middle of the machine. In the Northwest corner is the old electric traction model board and on either side of the interlocking machine are the cabinets for the defect detector readouts.
In the northeast corner we see what look like some very old telephone equipment in the back and a newer rack of comms gear in front. I am not sure if the stuffed animal is some sort of mascot or what.
The Model Board is immaculately painted and given the small number of "shadows" (ripped out tracks badly blocked out) it may have been re-painted sometime within its life. I was stunned about how vibrant the colors were and my old 3 MP camera couldn't quite do them justice. The unevenness of the lettering hints that it was painted by hand, which is all the more impressive (sign painting is a lost art). Here we see the west end of the interlocking is more prominent and one can see the shadows for the old #2 track and fillout track, but no others.
Looking at the center section of the model board we see the evidence of the 15/17/19 ladder originally consisting of double slip switches. We also see the release timer indicators. This vintage of Model 14 made used of three "area" timers, each releasing a range of signals instead of a one to one correspondence. Short release for dwarfs is 1m and long release for high signals is about 4 minutes eastbound, 3 and a half minutes westbound and 3 minutes for the intermediate signals.
Here we have a close up of the East End of the interlocking, all controlled from the same machine. Note the East End has its own Air Supply and like the West End there are low air alarms for 45lbs and 20lbs of pressure. At 45lbs the operator had to line all points for their most likely movement and at 20lbs he was to not attempt to throw them at all. Note the 22L and 28R signals on the East End are both displayed and traffic on #3 track is set to the West direction.
Here is another view of the West End showing the rusty rail notice sheet and release timer indicators.
Stepping back a bit we see the model board and the entire front of the 31 lever US&S Model 14 interlocking machine. The top of the machine is covered with can type blocking devices that fit over the thumb latch and prevent levers from being moved.
Here we have a view of the machine from the other side. Lever #1 was at the western portion of the plant and lever #31 at the eastern.
Here we see levers 1 through 9. As always even levers point down have three positions ( / | \ ) and are usually for signals. Odd levers that point up have two position ( / \ ) and are for switches and other binary state appliances. The signals are connected in opposing Left and Right (L and R) pairs which allow a single lever for each with the lever being moved Left or Right to display the corresponding signal. Despite being shiny I do not think lever 1 ever had a use. Lever 7 used to be a switch on the duckunder track that lead to a freight siding. Also note the knob below the indicator lamp panel that triggers and winds the rundown timer for canceling a signal. This timer applies to signals in the range 2 through 8.
Here we see levers 8 through 16. Because the center tracks through the station and many of the switches in the west end are infrequently used there are rusty rail blocking devices on every single switch lever. This reminded the operator to ensure that a route was clear due to rust possibly preventing trains from shunting properly. Lever 13 has TWO blocking devices one it, one for the rust and the other because in 2004 the Hill track would dump one out onto the ballast. Also note the second area timer knob below the indicator lamps that applied to signal levers in the range 10-20.
Here we see levers 17 through 26. Lever 23 used to control the old yard lead that has since been removed. Here we see third timer knob for East End signals in the range 22-28
Finally we see the levers 21 through 31. Lever 31 is the sole Traffic Control level that sets traffic on the bi-directional #3 track. Before BRYN MAWR caught fire the operator both at PAOLI and BRYN MAWR had to agree on the direction of the track by setting both their traffic control levers both in the proper direction (like a missile sub). After the fire the 31 lever in PAOLI gained sole control of traffic on #3 track. When #2 track west of the interlocking was converted to bi-directional operator in the 1960's it's direction was controlled from THORN tower. When the #31 lever is thrown it takes about 10-20 seconds for traffic to change as all of the bi-directional block signals have to switch to display the proper aspects in the direction of travel and Stop and Proceed against it. While this happens the track circuits bob causing the approach bell on the Model 14 to freak out and emulate some sort of slot machine.
To the right of the machine is a rather genetic readout for a combined Hotbox and Dragging Equipment Detector at Milepost 16.4 on tracks 3 and 4. This replaced a Servo Corporation unit that only had an HBD on track #3, which was typically used for freight.
The readout displays axle temp with little spines on thermal paper. The large spike at the end of each readout is the DED.
On the left side of the machine is a genuine article Servo Corporation HBD that inspects trains on track #1 at the current location of FRAZER interlocking. Definitely has that retro 50's charm!
Taking a step back we see a wider angle view of the tower showing the operator at work. To the right we have the refrigerator. To the left the cabinet of cleaning supplied. Between them are the Model 14 machine, Servo Corporation detector readout in the foreground and homebrew detector readout in the back. Lighting is provided by a bare white bulb. The replacement windows are small and don't let in a lot of light.
Here is the east view out of the tower. The windows all have rather nasty screens on them that don't allow for good photography.
Here is the west view showing the substation and hill track. To the far left is the old duckunder track.
On the operator's desk is the BRYN MAWR machine that controls the 4-track crossover at about Milepost 8. It is a typical panel design with individual function toggles exactly like the panel for FRAZER installed at THORN tower about the same time. Here we see signals displayed for trains on both #1 and #4 track, with the train on #1 track actually approaching the interlocking.
Here is a closer view of the panel now showing the train on #4 track approaching the interlocking. The large buttons on the model board are the signal toggles, the small buttons are blocking devices. BRYN MAWR has a pocket track on #4 track that allows locals to hold in the station while an express crosses ahead of them. When BRYN MAWR was rebuilt it was given #20 turnouts good for Limited Speed (45mph). Distant signals were upgraded via the use of Limited Speed Triangles instead of a flashing lower |. Fortunately nothing else was "upgraded" so features such as the bracket mast for track 4 at the exit to the pocket track survived. BRYN MAWR is controlled through some sort of modem data link that occasionally goes down.
On the operator's desk we see an old clock, the new telephone concentrator and the old telephone plug board as well as the new radio mic.
Next to the old phone plug boards are the Panel Blocking Devices. These were installed in the late 1940's to simplify the application of block devices when running trains against the flow of traffic. Blocking devices are applied to safeguard certain situations and cannot be removed without the dispatcher's permission. Normally applied to individual levers, panel blocking made it simple to lock out entire routes with the flip of a switch. Normal direction routes were default unblocked and reverse direction routes were default blocked. To change any of these the operator would get permission and then twist the knob to lock out or allow movements over a route. Here is the eastbound panel blocker slowing blocking knobs for 1, 2 and 4 track. Three track would have blocking applied to Lever #31. To see a panel blocking device in action for a reverse direction move see this photo from CORK tower.
Here is the westbound panel blocking device. The knob for the removed track #2 is in place, but out of service.
Continuing our tour we get to the PAOLI tower board. While it was not uncommon for interlocking towers in electrified territory to have breaker panels that controlled the overhead wire sections within the interlocking, PAOLI was the terminal of the original 1915 electrification scheme and as such predated the centralized supervision of the substations that was adopted in the later stages. As such the power board in the tower not only turned on and off the local overhead segments, but also handled switching at the substation. In the late 1930's when a new sub-station was installed with feeds from the 132Kv transmission system it too was wired into PAOLI's local board. Eventually the 1915 substation was closed when freight traffic left the line, but the 1930's panel probably soldiered on until the power dispatching in this area was computerized in the 1980's.
Here is a fully annotated large format photo of the PAOLI power board that can explain things better than I can.
Swinging around we see the supply cabinet and the bathroom cubicle located in front of the staircase.
Both the toilet and the sink are probably not original. In 1896 any sort of indoor plumbing would have been cutting edge and speaks to the wealth of the PRR.
The rear of the model board has come dislodged revealing the state of the art in 1930's display technology as well as the attention bells.
Coming full circle we see the notice board dating from the 1980's and showing both a railroad that no longer exists (Conrail) and a division that no longer exists (Philadelphia).
Well I believe that is everything. In order to go out on a high note I am just going to throw up this picture of PRR #269 as it makes it way eastward from Paoli Station as it had for the past 50 years as the tower pulls the levers as it has for the past 115 years.
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