38 BALLAST. 



banks. Where there is trouble in heaving, or wet spots, the 

 material should be taken out to such depth and in such a man- 

 ner as to insure perfect drainage. Care must be taken to avoid 

 wasting ballast down the sides of slopes, or otherwise. 



The depth of ballast will be determined in accordance with 

 the local conditions, and the character and amount of ballast 

 already in place, if any. In general, not less than 8 ins. of 

 good material will be required under ties. 



TAMPING. 



Tamp the entire length of ties on new track. Special pains 

 should be taken to insure thorough tamping from end of tie to 

 1 ft. inside of rail. On old track the center should be filled 

 and lightly tamped. 



Tamp joint and second ties thoroughly. Thorough tamping 

 of the second tie from points is of equal importance with that 

 required by the joint ties, and will prevent the formation of 

 cracks starting from upper edge of splices by reducing the up- 

 ward deflection of joints when a wheel is over the second tie. 



Material for filling and ballasting must not be taken from 

 slopes of embankments. When ballasting is completed, the 

 track must be in perfect line, surface and gage, in accordance 

 with the stakes furnished by the engineer. 



BALLAST CROSS-SECTION. 



Rock ballast should be filled in level with top of tie from 

 center to 2 ft. outside of rail, slopes 1 to 1. 



Gravel ballast must be finished to the standard cross-sec- 

 tion, which is as follows: 



At the center and for 1 ft. on each side thereof, the top of 

 ballast will be even with the top of ties, and thence carried 

 out with a straight uniform slope, passing 4 ins. above bot- 

 tom of ties at ends, to a point 21 ft. outside of rail, thence to 

 an intersection with the roadbed, with slopes of 1^ to 1. 



If material is used which is more or less impervious to 

 water, the slopes should be carried to an intersection with 

 roadbed on a line with bottom of ties at ends. 



The practice of crowning the ballast above top of tie at cen- 

 ter causes dusty track and rots the tie at the center and is 



