Way back in the sands of time known as Yahoo Groups, there was an effort to compile all known errors and gotchas in Kozo Hiraoka’s book, The Pennsylvania A3 Switcher. Yahoo Groups went away and nobody seems to have archived it, but this errata survived on brave peoples’ hard drives. Someone recently sent it to me, so I have decided to clean it up, add my own thoughts, and host it here for everyone. I hope you find it useful!
Pennsylvania A3 Switcher Errata
Version 1.1: Aug 8, 2006 Initial release.
Original authour was Pat Young on Yahoo Groups. Reedited and updated by Quinn Dunki, May 2025
Likely Errors
These are dimensions that appear to be verifiably incorrect in the drawings.
Page 88
Figure 14-19 #5 Steam Chest Cover
The width of the bolt pattern is shown as 1-1/32″, which is incorrect. As shown on the steam chest in figure 14-15, it should be 1-5/16″
Page 103
Figure 17-9 #5 Combination Lever
1/16″ cut depth should be 5/64”.
Page 113
Figure 18-12 #12 Collar
Number of items should be 2, not 1.
Page 114
Figure 18-18 Pins
Number of item #20 should be 6, not 4.
Page 118
Figure 19-10 #9 Fork Arms
The forked arm opening should be moved down 1/32” to more fully wrap around the cock plug shaft.
Page 119
Figure 19-12 #13 Front bracket
1/2” length from hole centre to top of bracket should be increased by 1/32” to 17/32” to prevent the e-clip from scraping the top of the groove.
Page 132
Figure 23-1 Fire Box Hinge
The distance that it sticks out from the back head cover is not specified. The distance to drill the door hinge pin is given as 3/16”, but it looks like it should be 5/16″. To be sure, it should be determined by building the firebox door first and then do the sizing/locating afterwards.
Page 133
Figure 23-1 Fire Tubes
The boiler section view shows the fire tube diameter as 0.787”, but figure 23-11 on page 137 shows the tube sheets being bored to 0.752”. The correct fire tube diameter is surely meant to be 0.750” (a standard pipe diameter) rather than the 0.787” shown on page 137.
Page 160
Figure 25-25 Brass Nipple
It looks like the opening end for the steam pipe is too large and should be reduced to fit the outside diameter of the steam pipe (i.e. from 7/32″ to 3/16″).
.
.
Caveats
These are suggestions from other builders for things you might want to change. Apply your own judgment to these suggestions. Nothing here is iron-clad.
Page 64
Figure 10-3, Side Frames
It looks like the hole for the water feed line bracket (page 193 figure 33-11) has not been marked. Perhaps this is so that it could be located when the water feed line is to be installed.
Page 85
Figure 14-3 #1,#2 Cylinders
Note that there are two steam channels running from the left and right steam ports to the edge of the cylinders. This is difficult to see in the drawings. Each steam passage is a pair of parallel holes for increased volume.
The depth of the steam ports is not marked in the drawings. You can eyeball a reasonable value from other features in the drawings. 0.160” deep seems to work. It’s not critical- these features are just drill targets for the actual steam passages.
Page 76
Figure 12-14 #5 Crank Pin
You may wish to make this long and trim to size after all other components that attach to it are fitted.
Page 98
Figure 16-1 Guide Yoke Assembly
You may wish to take the guide yoke assembly width from the assembled frame width.
Page 112
Figure 18-3 #1,#2 Running boards
You may wish to wait to drill the holes for the left and right sides until the cab sides are done. You can then transfer the hole positions at that point to guarantee correct positioning in case you decide to move the holes out a bit. This is also true for the air cylinder holes.
Page 113
Figure 18-10 #10 Spring
You may find that the spring length is too long, but you can cut and season to taste.
Figure 18-13 #14 Reach Rod
You may wish to leave it a bit longer on each end and trim to size after final fitting.
Page 114
Figure 18-14, #15 Reverse Shaft
You may wish to leave it a bit longer on each end and trim to size after final fitting.
Page 121
Figure 20-8 #6 Plunger
Figure 20-10 #8 Eccentric Rod
You may feel that the 1/8″ radius on the end of the eccentric rod is too flimsy, and it can be increased to 5/32″. This necessitates the plunger notch’s depth be increased to 11/64″.
Page 126
Figure 21-15 #14 Spring Pawl
The spring pawl that attaches to the lever may need to be lengthened from 1/2″ to 9/16″ to be able to ratchet correctly.
Page 130
Figure 22-7, #4 Ash Pan
The pan may be prevented from dropping down if the edge rubs against the grate support at #2 and #3.
Also, you may wish to locate the ash pan latch pin (#7) after assembling the ash pan latch on the right grate support (#2) to make sure that the pin is correctly engaged by the latch.
Page 132
Boiler Shell
It is all too easy to create the boiler shell too large because of mis-interpretation of the complicated boiler views on page 132. Another option is to create the smokebox shell first and then fit all the boiler components against it.
Page 142
Figure 23-26 Bell Stud
Do not be confused and end up tapping the inside of the bell stud to 1/4-32. It is 5-40 as shown on page 176, figure 29-17. The 1/4-32 threads shown on page 142 are in the copper shell, to retain the studs during silver soldering.
Page 153
Figure 25-3 #1 Smokebox
Before marking and cutting the openings for the smokestack, double-hole brass plate on the bottom of the smoke box, and steam inlet pipes, assemble the smoke box with the boiler and on the frame. Then use the cylinder tee’s steam openings to get the centre of the openings for the stack and brass plate.
Page 159
Figure 25-21 #14 Smokebox Saddle
The length of the front and back of the saddle should be increased/decreased to provide good placement of the boiler. Yours may be short by 3/32″ (i.e the height may need to be increased from 1 1/16″ to 1 5/32″).
Page 167, 170
Figure 28-4 #1 Throttle
Figure 28-18 #16 Snifting Valve
The snifting valve is specified with a 12-32 thread. This is a very strange thread, so you may wish to use either a 10-32 or a 1/4-28.
Page 174
Figure 29-11 Sandbox Cap Plug
If one wants a smooth, continuous contour, finish the outside cap profile based on the sand dome instead of the profile shown in the book.
Page 175
Figure 29-14 Sandbox Dome Connector
The routing for the sand dome connector in the sand dome seems too complicated. It seems that contouring the bottom of the sand dome connector and using a pin and screw to align it would be easier.
Page 180
Figure 31-1 #10, #11 Blower Valve
The blower valve is located on the leftmost bushing connection, but photo 31-3 on page 183 shows the blower valve on the rightmost bushing. In looking at the layout of the other controls (notably the whistle button) the layout shown in the photograph seems better. You may decide otherwise.
Page 185
Figure 32-1 Cab Front
The notch on the boiler outline that is 1-1/4” from the centre line of the front is on the right side. Make sure not to put the notch on the wrong side.
Page 189
Figure 33-1 Water Feed Line, Right Side
When running the water feed line on the right side, keep in mind the sand piping. You may find that you have to bend the water line leading from the check valve earlier than shown in the diagram.
Page 189
Figure 33-1 #20 Bypass Valve Water Pipe
The profile diagram from the cab side (below Detail B) shows the water pipe from the T-Joint to the bypass valve is a straight run. You may find that the pipe rubs against the boiler sheet, and you may wish to add another bend to move the pipe out further.
Figure 33-1 #19 Water Feed Line To Suction Ring Of Axle Water Pump
The side view shows the coupling to suction water feed line being parallel to the track. In order to do this one can move bracket #12 up or a bend can be put in water feed line.
Figure 33-1 Bypass Valve Location
The bypass valve as shown seems to position it where it is difficult to get fingers in there to turn the valve handle because of its closeness to the water glass. Bringing the valve out an 1/8″ would make the valve much more accessible.
Page 193
Figure 33-11 #12,#13 Water Feed Line Bracket
The mounting holes on the frame have not be located on page 64 (Figure 10-3). To actually locate and drill the bracket hole, some of the locomotive’s components (like the air compressor and running board) will have to be removed.