US SIGNALLING TOWERS
by Mike Brotzman
1. Bryn Mawr
The tower at Bryn Mawr sits on the Main Line. This
was the ex Pennsylvania RR east/west main from Philadelphia to Pittsburgh. In
1915 this 4-track line was electrified about 20 miles to Paoli. With easy MU
transport into the city the main line quickly became the home of the social
elite. Bryn Mawr tower was most likely built around 1915 and it served as a
block station. In this function the tower controlled the 6 switch cross over
and the local signals.
Bryn Mawr is built in the classic PRR style with a bay window,
brick base, cream wooden second story, slate roof and internal staircase. Bryn
Mawr is a fine example of second-generation PRR towers. This brick wood combo
supplanted the all wood 1890's version. Bryn Mawr ceased operation in 1994 due
to a fire and you can see the new remote interlocking to the left of the tower.
The ramp on the right is for handicap access to trains. In the US only the
interlocking gets the name plate and because the tower is no longer in service
the Bryn Mawr sign has been transferred to the new relay sheds.
Here is a view from farther down the platform. The
yellow wooden palettes on the tracks are to facilitate access to the inner
tracks. In the distance you can see the signals. There is a signal bridge and a
black signal mast on the tower side. Amtrak still uses the former PRR position
light signals. Each round signal has up to 7 yellow lights. A vertical line is
clear, diagonal is caution and horizontal is stop. The signals on the bridge
have 2 aspects to convey such information like go slow, go less slow, stop then
go, etc. (Check out the signal rules page at Eastern Railroad News for the
complete list of aspects. This link is in the "links" section I believe.) The
mast signal was showing clear when I took the picture and I have enhanced it
slightly for better visibility.
This last shot does not show the tower, but it does show the 1915
Bryn Mawr sub-station. You can also see the eastern signal-bridge. The line is
not have bi-directional signaling and the signals only face the flow of
traffic. The rest of the line is controlled by automatic block signals. At this
point the line retains the PRR 152 lb./yard jointed rail. The rail is old and
badly bowed in the middle so new welded rail is being installed. Amtrak's
Harrisburg line is one of the few lines with enough traffic to warrant signal
towers. From Paoli to Philly Amtrak shares the line with SEPTA which provides
MU service. At rush hour there is a train every few minutes. The remaining
towers on the Harrisburg line include ZOO, Overbrook, Bryn Mawr (closed),
Paoli, Thorn (Thorndale), Park (Parksburg, closed), Cork (Lancaster) and State
(Harrisburg). Bryn Mawr's operations have been transferred to Paoli.