When vitrified sewer pipe is used to drain a side ditch, the pipe joints are
closed tightly to prevent dirt from entering and clogging the pipe.
(Each question of this kind consists of a series of statements related to the
stem that precedes them. Indicate which are true and which false with respect
to the stem.)
Water pockets are a great nuisance to the track maintenance crew. They are
Created by operating numerous heavy trains over poor quality ballast.
Caused by pumping ties.
The cause of heaving roadbed.
The result of soil erosion.
Caused by porous material surrounded by impenetrable material.
A good roadbed is essential to a railroad because it:
Receives train weight from ballast above and transmits it to ground
Compensates for irregularities of terrain.
Supports ballast above adjacent ground to provide run-off for water.
Provides the stability that a track needs.
Should be spongy to reduce shock to rails and provide a comfortable
As a track supervisor in an oversea area, you would select new ballast on the
basis of the: