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RP-12.1 Turnout Dimensions
O Scale
Look here for a larger printable copy of this diagram.
Original Design by Allen Hazen
Modified
by Clarence H. Hill
Jump to Frog Numbers 8, 9, & 10.
| (1) | FROG NUMBERS | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|
| PROPERTIES OF CURVED SWITCHES | |||||
| (2) | Rail Length | 3-5/8" | 3-5/8" | 3-5/8" | 5-3/4" |
| (3) | Point Angle * | 2d 01' | 2d 01' | 2d 01' | 1d 20' |
| (4) | Heel Spread [+] | 7/32" | 7/32" | 7/32" | 7/32" |
| (5) | Heel Angle * | 4d 33' | 4d 33' | 4d 33' | 2d 46' |
| (6) | Switch Radius | 83" | 83" | 83" | 228" |
| (7) | Mid-Ordinate | .021" | .021" | .021" | .018" |
| LEAD TO THEORETICAL POINT OF FROG | |||||
| (8) | Lead | 9-9/16" | 10-3/4" | 11-7/8" | 16-3/16" |
| CLOSURE DISTANCE | |||||
| (9) | Straight Rail | 5" | 6-1/8" | 7-1/8" | 9-1/8" |
| (10) | Curved (Length) | 5-3/32" | 6-7/32" | 7-3/16" | 9-3/16" |
| (11) | Rail (Radius) | 30" | 52" | 83" | 98" |
| GAGE LINE OFFSETS ON CURVED CLOSURE RAIL | |||||
| (12) | 1st Point Y1 [+] | 7/16" | 7/16" | 7/16" | 3/8" |
| (13) | 1st Point X1 | 5-5/8" | 5-7/8" | 5-15/16" | 8-3/8" |
| (14) | Mid-Point Y2 [+] | 19/32" | |||
| (15) | Mid-Point X2 | 10-15/16" | |||
| (16) | 3rd Point Y3 [+] | 11/16" | 11/16" | 11/16" | 13/16" |
| (17) | 3rd Point X3 | 7-1/16" | 7-5/8" | 7-15/16" | 12-23/16" |
| PROPERTIES OF FROGS | |||||
| (18) | Frog Angle * | 14d 15' | 11d 25' | 9d 32' | 8d 10' |
| (19) | Overall Length | 2-9/16" | 2-13/16" | 3-1/8" | 3-1/2" |
| (20) | Toe Length | 15/16" | 1" | 1-1/8" | 1-5/16" |
| (21) | Heel Length | 1-5/8" | 1-13/16" | 2" | 2-3/16" |
| (22) | Toe Spread | 15/64" | 13/64" | 3/16" | 3/16" |
| (23) | Heel Spread | 13/32" | 23/64" | 21/64" | 5/16" |
| POINT OF FROG TO INTERSECTION OF CENTER LINES | |||||
| (24) | PF to ICL | 5" | 6-1/4" | 7-1/2" | 8-3/4" |
| DATA FOR CROSSOVERS -- PF to PF ON PARALLEL TRACKS | |||||
| Distance for 4" Track Centers Along: | |||||
| (25) | Straight Track | 5-3/4" | 7-5/16" | 8-13/16" | 10-3/8" |
| (26) | Crossover Track | 6-1/4" | 7-11/16" | 9-3/16" | 10-5/8" |
| Increment for 1/4" Change in Track Centers Along: | |||||
| Straight Track | 1" | 1-1/4" | 1-1/2" | 1-3/4" | |
| Crossover Track | 1" | 1-1/4" | 1-1/2" | 1-3/4" | |
Return to Frog Numbers 4, 5, 6, 7
| (1) | FROG NUMBERS | 8 | 9 | 10 |
|---|---|---|---|---|
| PROPERTIES OF CURVED SWITCHES | ||||
| (2) | Rail Length | 5-3/4" | 5-3/4" | 5-3/4" |
| (3) | Point Angle * | 1d 20' | 1d 20' | 1d 20' |
| (4) | Heel Spread [+] | 7/32" | 7/32" | 7/32" |
| (5) | Heel Angle * | 2d 46' | 2d 46' | 2d 46' |
| (6) | Switch Radius | 228" | 228" | 228" |
| (7) | Mid-Ordinate | .018" | .018" | .018" |
| LEAD TO THEORETICAL POINT OF FROG | ||||
| (8) | Lead | 17-5/16" | 18-3/8" | 19-3/8" |
| CLOSURE DISTANCE | ||||
| (9) | Straight Rail | 10-1/16" | 10-15/16" | 11-3/4" |
| (10) | Curved (Length) | 10-1/8" | 11" | 11-25/32" |
| (11) | Rail (Radius) | 132" | 175" | 228" |
| GAGE LINE OFFSETS ON CURVED CLOSURE RAIL | ||||
| (12) | 1st Point Y1 [+] | 3/8" | 3/8" | 3/8" |
| (13) | 1st Point X1 | 8-7/16" | 8-1/2" | 8-5/8" |
| (14) | Mid-Point Y2 [+] | 19/32" | 19/32" | 19/32" |
| (15) | Mid-Point X2 | 11-5/16" | 11-5/8" | 11-7/8" |
| (16) | 3rd Point Y3 [+] | 13/16" | 13/16" | 13/16" |
| (17) | 3rd Point X3 | 13-7/16" | 14" | 14-1/2" |
| PROPERTIES OF FROGS | ||||
| (18) | Frog Angle * | 7d 09' | 6d 22' | 5d 43' |
| (19) | Overall Length | 4" | 4-1/2" | 5" |
| (20) | Toe Length | 1-1/2" | 1-11/16" | 1-7/8" |
| (21) | Heel Length | 2-1/2" | 2-13/16" | 3-1/8" |
| (22) | Toe Spread | 3/16" | 3/16" | 3/16" |
| (23) | Heel Spread | 5/16" | 5/16" | 5/16" |
| POINT OF FROG TO INTERSECTION OF CENTER LINES | ||||
| (24) | PF to ICL | 10" | 11-1/4" | 12-1/2" |
| DATA FOR CROSSOVERS -- PF to PF ON PARALLEL TRACKS | ||||
| Distance for 4" Track Centers Along: | ||||
| (25) | Straight Track | 11-7/8" | 13-3/8" | 14-7/8" |
| (26) | Crossover Track | 12-1/8" | 13-5/8" | 15-1/8" |
| Increment for 1/4" Change in Track Centers Along: | ||||
| Straight Track | 2" | 2-1/4" | 2-1/2" | |
| Crossover Track | 2" | 2-1/4" | 2-1/2" | |
* the d stands for degrees (2d 01' is 2 degrees 01 minutes)
NOTES
a. Recommended to use gages for dimensions marked [+]
b. Switch heel joints should not be out of square more than 1/32".
c. Refer to RP-15.1 for suitable rails.
d. Slip-on joint bars may be used up to 3/4" long and B&S gage No.
26 thick. The fit must be snug on the base of the rail.
Return to Frog Numbers 4, 5, 6, 7 or 8, 9, & 10.