TABLE OF DIMENSIONS OF A PRATT'S TRUSS.

| | | Upper | Lower | Main Brace Rods. | Counter | | | |
Clear| | No.| Chord. | Chord. | | Rods. | | | Posts. |
Span |Rise| of |---------|---------|--------------------|-----------| | |----------|
in | in |Pan-|No.| |No.| |No.| Size |No.|Size.|Num| |No.| Size|No.|Size. |
feet.|feet|els.|Pcs|Size.|Pcs|Size.|Ctr|Centre|End| End.|ber| Size. |End| End.|Ctr|Centre|
-----|----|----|---|-----|---|-----|---|------|---|-----|---|-------|---|-----|---|------|
25 | 6 | 8 | 3 | 4x5 | 3 | 4x10| 2 |1 | 2 |1-3/8| 1 |1-7/16 | 3 | 4x5 | 3 | 4x4 |
50 | 9 | 9 | 3 | 6x7 | 3 | 6x10| 2 |1-3/16| 2 |1-1/8| 1 |1-5/8 | 3 | 6x6 | 3 | 6x5 |
75 | 12 | 10 | 3 | 6x9 | 3 | 6x11| 2 |1-5/16| 2 |2-1/2| 1 |1-7/8 | 3 | 6x7 | 3 | 6x5 |
100 | 15 | 11 | 3 | 6x10| 3 | 6x12| 2 |1-7/16| 2 |2-7/8| 1 |2 | 3 | 6x9 | 3 | 6x7 |
125 | 18 | 12 | 4 | 6x10| 4 | 6x13| 2 |1-1/2 | 2 |2-3/8| 1 |2-1/8 | 4 | 6x9 | 4 | 6x7 |
150 | 21 | 13 | 4 | 8x10| 4 | 8x14| 3 |1-5/16| 3 |2-1/2| 2 |1-5/8 | 4 | 8x8 | 4 | 8x7 |
175 | 24 | 14 | 4 |10x12| 4 |10x15| 3 |1-5/8 | 3 |2-3/4| 2 |1-11/16| 4 |10x10| 4 | 10x8 |
200 | 27 | 15 | 4 |12x12| 4 |12x16| 3 |1-1/2 | 3 |3-1/8| 2 |1-13/16| 4 |12x10| 4 | 10x8 |

This table is partly given in Trautwine's Engineer's Pocket Book, and
partly made up from directions therein given.


TABLE OF DIMENSIONS FOR SMALL SINGLE TRACK PRATT TRUSSES.

At centre At end Centre End
Clear Chords Centre End of truss, of truss, Counter, Counter,
Span, each, Post, Posts, Diam. of Diam. of Diameter, Diameter,
Ft. Ins. Ins. Ins. Rods. Rods. Ins. Ins.

30 9 x 11 4 x 9 7 x 9 1 1-5/8 1-3/8 1