Handbook of Railroad Construction; For the use of American engineers. / Containing the necessary rules, tables, and formulæ for the location, construction, equipment, and management of railroads, as built in the United States.

by George L. Vose

A	8,007,500
B	204,500
C	1,442,500
D	3,640,000
E	1,170,000
F	600,000

showing not only a great difference in the unit resistance taken, but also in the effect of the ratio between the length and diameter.

Such being the discrepancy, there will be given no formula; but in place of such, the table following, which is calculated from the rules least opposed to experimental evidence.

TABLE SHOWING THE LOAD IN POUNDS SAFELY BORNE BY CAST-IRON COLUMNS.
HOLLOW CYLINDERS.											H AND + SECTIONS.
Diameter in inches.	Length or height in feet.									Metal thickness.		Length or height in feet.
	6	8	10	12	15	18	20	22	24			6	8	10	12	15	18	20	22	24
2	6000	5000	4000	3000	2500	1800	1500	1300	1100	¼		4000	3000	2400	1800	1400	1100	1000	900	800
3	16000	14000	13000	11000	9000	7000	6000	5000	5000	⅜		12000	11000	10000	9000	8000	7000	5000	4000	3000
4	30000	29000	26000	24000	22000	18000	16000	14000	13000	½		25000	23000	21000	18000	16000	13000	12000	9000	6000
5	50000	37000	45000	42000	39000	37000	31000	28000	26000	⅝		36000	34000	31000	28000	25000	23000	21000	20000	18000
6	59000	57000	55000	52000	49000	44000	41000	38000	36000	¾		40000	38000	37000	36000	35000	34000	32000	30000	28000
7	101000	99000	96000	92000	88000	81000	76000	72000	68000	13 16		60000	59000	58000	57000	56000	54000	53000	51000	49000
8	131000	129000	126000	122000	118000	109000	105000	100000	96000	⅞		100000	98000	96000	94000	91000	88000	83000	78000	70000
9	169000	167000	164000	160000	156000	146000	141000	136000	131000	1		140000	130000	126000	120000	114000	110000	106000	100000	90000
10	210000	200000	200000	200000	190000	180000	180000	170000	170000	1⅛		190000	180000	170000	160000	150000	140000	130000	125000	120000
11	250000	250000	240000	240000	240000	230000	220000	220000	210000	1¼		230000	220000	210000	200000	190000	180000	170000	160000	150000
12	300000	300000	290000	290000	290000	270000	270000	260000	260000	1½		280000	260000	250000	240000	230000	220000	200000	190000	180000
14	450000	430000	410000	380000	370000	350000	330000	320000	300000	1¾		360000	320000	310000	300000	290000	280000	270000	260000	240000
16	520000	500000	480000	460000	440000	420000	400000	370000	350000	2		460000	430000	400000	370000	350000	330000	310000	300000	280000
18	650000	630000	610000	590000	560000	520000	470000	430000	400000	2½		560000	530000	510000	480000	440000	410000	380000	350000	330000
20	800000	760000	740000	690000	650000	590000	540000	490000	450000	3		600000	580000	550000	520000	500000	460000	430000	400000	380000
Diameter in inches.	6	8	10	12	15	18	20	22	24	Metal thickness.		6	8	10	12	15	18	20	22	24
	Length or height in feet.											Length or height in feet.

OF THE TRUSS.

171. The most simple bridge that could be built, consists of a single piece of timber placed across the opening to be spanned. This form is applicable to spans under twenty feet. The proper dimensions are found by the formula:—

d = √(4wL
5000b) = the depth.

Example.—The depth of a beam of twenty feet span, and twelve inches wide, to support a load of twenty thousand two hundred and fifty lbs. is

d = √(4 × 20,250 × 20 × 12
5000 × 12) = 18 inches.

A beam 12 × 18, and of 20 feet span, will therefore bear safely a load of 20,250 lbs., applied at the centre.