Signals | O-Scale | PRR-Style

PREMIER PENNSYLVANIA POSITION LIGHT SIGNALS, PRR-Series

This style of signal was used on the Pennsylvania Railroad as well as the early Norfolk & Western (pre 1962) and the Long Island Railroads. The aspects were determined by the angle position of the three lights. The lights arranged in a vertical position means a clear aspect. The lights arranged in a diagonal position from upper right to lower left means an approach aspect. The lights arranged in a horizontal position means a stop aspect. The lights arranged in a diagonal position from upper left to lower right means a restricted aspect. With its fog penetrating yellow and a single bulb failure not affecting the display, it is considered one of the safest signals to ever be developed.

The PRR used a single target signal or a double target signal. There were no triple target signals for the PRR. The upper target always had a full round background even though it was not necessary to display all aspects on the upper target. The lower target came in a variety of shapes and arrangements depending on the speed restrictions and the environmental conditions. Atlas-O and Custom Signals will be offering a variety of these signals to cover most requirements.

Since the PRR was primarily a 4 track main line, many signal bridges were used. Custom signals will be producing a limited supply of bridge versions for the PRR style signals.  The bridge versions end with a 2 and the ground versions end with a 5.

PRR-2, 6925.  Atlas will be offering the single target ground signal with the lower marker light (#6925).  Custom Signals will be offering the same style signal as a bridge signal (PRR-2).  These signals are intermediate signals used as ABS block signals.  They will display normal speed indications only.  These are indicated in the TCL as a circled target number such as “1W”.  This means that this is a full target and will display 3 “colors” or aspects.  The automatic sequence will be CLEAR, STOP, APPROACH and CLEAR.  Using the lower marker light will replace the STOP with STOP AND PROCEED if desired.  If you need an absolute signal, such as at a junction, the lower marker light would be disconnected.

PRR-15.  This bidirectional signal has been in the PRR signal books since the 1920's.  It was rarely used until around 1984 when the DOT allowed railroads to place signals on either side of the track. 

Custom Signals will be offering this style signal as a ground version only.  This version acts as 2 intermediate signals used as ABS block signals.  They will display normal speed indications only.  These are indicated in the TCL as a circled target number such as “1W”.  This means that this is a full target and will display 3 “colors” or aspects.  The automatic sequence will be CLEAR, STOP, APPROACH and CLEAR. 

I did not place the lower marker light below the main target  Instead, this signal has the mile post sign below the target.  Any signal having a mile post sign mounted on the post is considered a STOP AND PROCEED signal.  A set of signal decals will be included with each signal.  

One of the big advantages of this signal is for double track main lines.  Two of these signals can replace 4 individual bridge signals for a double track main lines.  This was realized by the railroads years ago.

PRR-22, 25.  Custom Signals will also make this Medium/Limited/Restricted speed indication signal.  This signal will have a fixed horizontal display on the top target (R for Red in the TCL) so normal speed indications are not possible.

This top target is used with the lower target to display medium, limited or restricted aspects only.  One automatic sequence is MEDIUM CLEAR, STOP, SLOW APPROACH and back to MEDIUM CLEAR.  You can also have the automatic sequence MEDIUM CLEAR, STOP, RESTRICTED and back to MEDIUM CLEAR.  You can choose either one of these automatic sequences for the diverting route.  The medium clear can also be bypassed in either case.  This signal would be used at the end of passing sidings, junctions or anywhere you see the R /# symbol in the TCL.

This signal would be used where the train would have to take a diverting route or where normal speeds would not be permitted. This is generally where the number of tracks was decreasing and the train had to move to another track. One such location would be at the end of a passing siding.   

If you have more than one diverting route at this location, you can use both of these sequences above, one for each of the different routes.  You will have to purchase another Signal Control Board, BSC-3, from Custom Signals.  This signal could now be used at the end of passing siding where you had 2 main lines to enter.  A following crossover would allow you to go onto either main line.  You will see these situations where you have the R /# /# symbol in the TCL.

You can add LIMITED speed indications by using the BSF-2, Block Signal Flasher with this signal.

PRR-42, 45.  You will find many uses for the double target signal in the TCL.  Custom Signals will produce the PRR-42 and PRR-45 series signal for this purpose.  This signal will display Normal, Medium, Limited or Restricted speed indications.  This signal would be used where there is a choice to remain on the main line at normal speeds or to divert to another track at slower speeds.  One route is usually a main line for the normal speeds (top target).  This target will give the same sequence as the Atlas #6925 signal above.  The bottom target is for a diverting route at slower speeds.  This will give the same aspect choice as the PRR-22 and -25 signals above.  These are indicated in the TCL as #/# symbol.  This signal will come with 2 BSC-3 signal control boards,      

You can add LIMITED speed indications by using the BSF-2, Block Signal Flasher with this signal.

PRR-52, 55.  Throughout the TCL you will also find 3 target signals.  The basic function of a 3-target signal is to display all possible signal aspects.  The top target is for normal speeds.  The middle target is for medium and limited speeds (generally flashing).  The lower target is for slow speeds.  Applying the PRR signal to the TCL presents a problem since it only has at most 2 targets. 

My solution for the 3 target signal problem is the PRR-52 and PRR-55 version.  Structurally these are exactly the same signal as the PRR-42 and PRR-45 signals except they come with 3 signal controllers.  Two of the controllers are used the same way as the 42/45 version above.  The third controller is used in place of the bottom target in the TCL and displays restricted speeds on the same PRR lower target.  This is used for a second diverting route where restricted speeds are needed.  The automatic sequence is MEDIUM CLEAR, STOP, RESTRICTED and back to MEDIUM CLEAR.  Again the Medium Clear can be omitted in this sequence.

As you can see, there are no “SLOW SPEED” aspects displayed on either the bridge or ground signals.  The PRR generally used a dwarf signal for slow speeds.  If you want Normal, Medium or Limited and Slow speeds, you need to use the PRR-42 or PRR-45 series signals with a PRR 11 dwarf in place of the 3rd target.  This will give either of the automatic lower target aspect sequences above with the dwarf signal’s slow speed aspects substituting for either one of the lower target signal sequences.  Call or e-mail Custom Signals for more help.

You can add LIMITED speed indications by using the BSF-2, Block Signal Flasher with this signal.

PRR-11.  Custom Signals will also be producing the PRR-11 Dwarf signal.  Unlike the ground and bridge signals, the dwarf will display a golden white light just like the real dwarf.  Using the dwarf SCB included with the signal, it will display all 4 dwarf aspects SLOW CLEAR, SLOW APPROACH, RESTRICTING and STOP. 

There will also be 2 automatic sequences possible.  First will be SLOW CLEAR, STOP, SLOW APPROACH and SLOW CLEAR.  The second will be SLOW CLEAR, STOP, RESTRICTED and SLOW CLEAR.  In either case, the Slow Clear can be omitted.  The dwarf can be used anywhere the dwarf is shown in the TCL.  The dwarf is shown by a hexagon shape.

I hope that this helps to clear up the different PRR signals and how they can be used.  As you can see from the photos in the left column, Custom Signals will make every effort to capture all the detail of the prototype PRR signals.  Each of the ground signals will come with ladder, platform railing and bolt details for each target. Each of the bridge signals will not have the these details, but come with prototypical brackets to mount the signals to most of the common O-scale bridges produced.  All of the models will have the mounting brackets and hood details shown on the PRR-15 at the left.

You should make sure that you have an accurate signal plan before you start purchasing signals.  If you need any more help, please call or e-mail. 

As with all the other signals from Atlas and Custom Signals, you can increase the number of aspects on each of the PRR signals by using the BSF-2, Block Signal Flasher. You can find more information about this PCB in the Electronics Section.