Lot #302 - Diesel Locomotive Cab Signal Indicator
We don’t see many of these in New
England. It is technically called an ADU (Aspect Display Unit). It is made
of cast metal with a glass panel insert with stencils for signal
indications. This is a 4 signal model. It would have been mounted
vertically. Because it is positional and not color based it is probably
Pennsylvania Railroad and not New Haven. Used in passenger service the 4
signals are: Clear, Approach Medium, Approach, Restricting. Approach Medium
used both a vertical and diagonal signal. The clear glass is cracked and it
could be swapped out. It has a cast number of "166285B" on the
inside. It measures 15" by 4" and it has the mounting hangers on
the ends. I think that these were just used in passenger service because of
the time required to reduce speed quickly on a freight haul wouldn't really
work. Very dirty but good basic condition. From another employee: This is indeed PRR style, and the N & W also used
position of light signals, though I do not know if they had cab signals on
their mains. Please know that as a veteran engineer of many freight trains
on the old PRR lines, we most certainly did have our freight locomotives
equipped with ADU's like this and yes it did take longer to get slowed down
to the signal that the cabs were showing. I've done it with coal trains and
they do take longer than a passenger train would to comply with the cab
signal but you can get them slowed before the cab signal drops to an even
slower speed. The cab signals come up way before the wayside signals to
which they correspond, to give a heavy train the time it needs to get
slowed. Your unit would have been used on diesel and electric locomotives
alike and also on electric commuter coaches. I spend five nights a week
looking at a modern version of this ADU on my Amtrak trains.
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copyright Scott Czaja 201 
mi35
Railroad
Pennsylvania ?
Size
4" by 15"
Date
vary
Condition
Good +