RAILROAD SIGNALS of the U.S.

The above photo was taken in 1974, on a trip to New Haven CT on the Northeast Corridor via Amtrak. During this period, Amtrak was still using heritage fleet cars, and you could easily take pictures out of the vestibules. This picture was taken somewhere in the Bronx.
MECHANICAL DRAWINGS
Here are some scans out of a US&S catalog from the 1930's:
PICTURES
Mechanical semaphores protecting a B&O / PRR Diamond
(For more info click here)

Baltimore's last Semaphore

Baltimore's last semaphore on the CSX going into Gray's Yard (Sparrows Point),
with a permanent restricting aspect.
The signal was taken down in 2006 by CSX.
The Semaphore's in and around Mason City, IA
The last Semaphore on the Southern Tier, NY
Train Order Semaphore in Iowa City IA
Train Order Semaphore in Waltham MA
New: 1-10-2007
Last Modified:
15-Mar-2008