The following track diagram will apply to this part.
If you forgot all of the photos can be seen at:
http://acm.jhu.edu/~sthurmovik/Railpics ... art-3.html
The summit of the Alleghenies, like most mountain railroad summits, features a complex of tracks that enables the use of helpers to be cut off and return to base and also accommodate any reductions in main tracks due to tunnels and junctions of alternate / low grade routes. The Gallitzin Summit is not different and at one point featured all of those in a giant interlocking complex known as BN-SF-AR-UN, seen here in this 1948 chart. After a signaling consolidation project during World War 2, the entire complex was controlled from a pair of US&S Model 14 interlocking machines in a new all brick tower overlooking AR interlocking overlooking tracks 1 and 2 with a logically seperate yet direct wire controlled UN interlocking on tracks 3 and 4. East of AR and UN was the previously mentioned SF interlocking where the Muleshoe Curve route diverge and before that was BF that provided a trailing point pre-processing ladder.
Today only AR and UN remain as active interlockings and the tower was closed in 1994. Today CP-AR serves as the eastern end of two sidings off track 1 that run between there and CP-MO. CP-UN acts as a crossover between tracks 2 and 3. Finally, between AR and UN runs a loop track that helper sets (or excursion trains) can use to turn back to Altoona after helping a westbound train over the grade. CP-UN used to have a 3-track PRR signal bridge for westbound movements, but around 2009 it was replaced by a color light cantilever due to structural issues. We can see it here with the 12W and 14W signals.
#15 switch crossover with pneumatic switch machines.
The slow speed loop track splits off between the two crossovers on the #11 switch.
The relay hut is located in the crook of the loop track, adjacent to the #11 crossover.
The restricting-only 14E reverse direction dwarf follows immediately on the Rule 251 West track #3.
Around a bend sits the 12E-1 signal sitting all alone on a 2-track PRR signal gantry. The lower head only offers a Restricting indication as the only routes available are straight ahead or against the flow of traffic on track #3. Back in the day this used to support two semi-automatic exit signals for westbound movements.
After leaving CP-UN we pass under the 2493 automatic, which is for westbound movements on tracks 3 and 4 only. Yes you heard me right, between CP-UN and CP-MO the tracks are renumbered 0 through 4 due to the presence of two siding tracks on the other alignment and thus track 3 becomes 4, 2 becomes 3 and we have a new tracks 2 and 0. This automatic is also distant to CP-MO, mounted on a two track late model gantry and if you look at the bottom | you can see the old mounting bracket for a Limited speed triangle.