You are starting a train on a fairly steep ascending grade and in curved territory. How do you avoid a string-line derailment?

You are starting a train on a fairly steep ascending grade and in curved territory. How do you avoid a string-line derailment?

• A. Increase power to maximum before brakes release
• B. Keep brakes applied until movement begins
• C. The following: (1) Allow the train brakes to fully release before starting and (2) Use only enough power to start the train
• D. Use only the independent brake

Answer: (C)

The idea is to start smoothly so the train doesn’t pull into a straight line on the curve. On a steep grade with curves, a sudden, heavy start can pull the cars taut and cause stringlining, where the train tries to follow a single straight path rather than the curved track. Release all brakes before you move. If any brakes are still holding, they create pre-load and resistance that the locomotive must overcome, often leading to a jerky or abrupt start once motion begins. By letting the brakes fully release, you avoid this pre-load. Then use only enough tractive effort to start moving. Too much power at the moment of starting on a curve can pull the train taut and exaggerate any mismatch between wheels and rails, increasing the risk of stringlining. A measured, gradual start keeps forces in check and helps the train follow the curved path safely. In short: release brakes before movement and apply just enough power to begin moving.

The idea is to start smoothly so the train doesn’t pull into a straight line on the curve. On a steep grade with curves, a sudden, heavy start can pull the cars taut and cause stringlining, where the train tries to follow a single straight path rather than the curved track.

Release all brakes before you move. If any brakes are still holding, they create pre-load and resistance that the locomotive must overcome, often leading to a jerky or abrupt start once motion begins. By letting the brakes fully release, you avoid this pre-load.

Then use only enough tractive effort to start moving. Too much power at the moment of starting on a curve can pull the train taut and exaggerate any mismatch between wheels and rails, increasing the risk of stringlining. A measured, gradual start keeps forces in check and helps the train follow the curved path safely.

In short: release brakes before movement and apply just enough power to begin moving.