Roy's Super Toy Shop
This site is dedicated to Pennsylvania Railroad Steam Locomotives
These numbers, 0-4-0, 4-6-2, 2-10-0, 4-6-4-4 and many other like them define the wheel layout of the steam engines and therefore the type and classification for them. The type is the name used by the builders and are the same for all builders and railroad lines.
The classification system is unique to each railroad line. The only line we are talking about here is the PRR so we will say a given type is a given class, but please remember if you look at another line's engine it will have a different classification.
O.K. So just what do these numbers mean? Like I said above, it's really very simple, they define the wheel layout of the steam engines. The first number is how many leading (or pilot) wheels the engine has, and the last number is how many trailing wheels the engine has. The middle number or numbers are how many driving wheels it has.
For our example we will use the Pacific, a PRR class K, wheel arrangement 4-6-2.
There are 4 small leading wheels that help steer the engine around curves.
There are 6 large driver wheels.
And there are 2 trailing wheels that support the firebox.
Giving us a 4-6-2.
In the examples here we will use the standard symbols of 'o' for
the small wheels and 'O' for the big wheels or drivers.
The '/' is the front of the engine.
Wheel layout Type PRR Class 0-4-0 /OO Shifter A 0-6-0 /OOO Switcher B 0-8-0 /OOOO Switcher C 4-4-0 /oo OO American D 4-4-2 /oo OO o Atlantic E 2-6-0 /o OOO Mogul F 4-6-0 /oo OOO Ten Wheeler G 2-8-0 /o OOOO Consolidation H 2-10-0 /o OOOOO Decapod I 2-10-4 /o OOOOO oo Texas J 4-6-2 /oo OOO o Pacific K 2-8-2 /o OOOO o Mikado L 4-8-2 /oo OOOO o Mountain M 2-10-2 /o OOOOO o Santa Fe N 4-4-6-4 /oo OO OOO oo ** Q 6-4-4-6 /ooo OO OO ooo ** S1 6-8-6 /ooo OOOO ooo ** S2 4-4-4-4 /oo OO OO oo ** T 0-8-8-0 /OOOO OOOO *** CC 2-8-8-0 /o OOOO OOOO *** HC 2-8-8-2 /o OOOO OOOO o *** HH** I do not know what these types are called, they are refereed to as 'Duplex' on some sites, except for the S2. If anyone knows the type of any of these (Q, S1, T, CC, or HC) please Send me an email I will give you credit on this page. If you have any references to cite I would appreciate you listing them.
3.) The POSITION light system with 3 lights for each signal. The lights are positioned
like the semaphore.
This is the system used on the PRR.
STOP . . .. . . .
CAUTION . .
4.) The COLOR POSITION light system with 3 colors, similar to the traffic lights on
the streets except they use 2 lights for each signal. The lights are positioned like
those in the description above with the center light removed.
a.) | RED means STOP
b.) / YELLOW means CAUTION
c.) _ GREEN means ALL CLEAR
Back to PRR index