14. The broken lines on the accompanying diagram indicate the guard rails on a two-track main
line (solid lines) as it enters an open-floor deck bridge. Which of the guard rails are
1 and 3.
1 and 6.
3 and 4.
2 and 5.
15. Ice in poorly drained tunnels creates a problem because it causes:
Rails to buckle.
Excessive weed growth the next summer.
16. The season during which limited visibility is a serious safety hazard for the track
maintenance crew is: