CDL General Knowledge Test · CDL General Knowledge Test
CDL General Knowledge Test: Railroad Crossings and Mountain Driving Concepts
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Overview
This chapter covers two places where a heavy vehicle has little room for error: railroad-highway crossings and long, steep grades. At a crossing, a train cannot stop for you. On a downgrade, gravity keeps pushing your speed up.
Approach every crossing expecting a train. Passive crossings have only signs and markings, so the decision is yours. Active crossings have flashing lights, bells, or gates. Do not race a train, do not rely only on signals, and do not shift gears on the tracks. A typical tractor-trailer needs at least 14 seconds to clear a single track and more than 15 seconds for a double track. If you get stuck, get out and away from the tracks, then call the emergency number posted at the crossing or 911.
Before a long downgrade, choose a safe speed for your weight, the grade, the road, and the weather, and shift to a low gear before you start down. Engine braking is your main speed control. Too much braking makes brakes fade from heat. Use the proper method: when you reach your safe speed, brake until you are about 5 mph below it, release, and repeat. Know where the escape ramps are.
Key concepts
Passive and active crossings
A passive crossing has no traffic control device, only signs and markings, so you decide whether it is safe. An active crossing has flashing red lights, with or without bells, and sometimes gates.
Memory tipPassive means the decision is all yours.
Time to clear the tracks
Plan on a typical tractor-trailer taking 14 seconds or more to get across one set of tracks, and over 15 seconds when there are two sets. Never start across unless you can get all the way over.
Memory tip14 seconds for one track, more for two.
Source: New York State DMV Commercial Driver's Manual (CDL-10), Section 2 · as of 2026
Stuck on the tracks
Get out of the vehicle and away from the tracks. Then use the emergency number posted at the crossing or call 911, and give the location and DOT number if posted.
Memory tipPeople first, truck second.
Brake fade
Loss of braking power when brakes get too hot from overuse. You must press harder and harder for the same effect, until they may not slow you at all. Brakes out of adjustment make fade worse.
Memory tipHot brakes are weak brakes.
Downgrade braking method
In the right low gear, when you reach your safe speed, brake hard enough to feel a definite slowdown. At about 5 mph below safe speed, release. The application lasts about 3 seconds. Repeat when you are back at safe speed.
Memory tipSafe speed, brake down 5 mph, release, repeat.
Source: New York State DMV Commercial Driver's Manual (CDL-10), Section 2 · as of 2026
Escape ramp
A long bed of loose, soft material, sometimes going uphill, built to stop a runaway vehicle. Signs show where they are. If your brakes fail on a downgrade, use one.
Memory tipKnow where the ramps are before you need one.
Often tested
- Do not shift gears while crossing railroad tracks.
- A typical tractor-trailer needs at least 14 seconds to clear one track.
- If you are stuck on the tracks, get out and away first, then call.
- Shift to a low gear before you start down a grade.
- Engine braking is the main way to control downhill speed.
- Brake to about 5 mph below your safe speed, then release.
3 sample questions
Verified practice questions from this unit.
Question 1. What should you do about shifting gears while crossing railroad tracks?
- ① Do not shift gears while crossing the tracks
- ② Shift up halfway across to clear faster
- ③ Shift into neutral and coast across
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Answer: ① Do not shift gears while crossing the tracks
Key point: Never shift gears on the tracks
Do not shift gears while crossing railroad tracks. A missed shift could leave you stuck on the tracks. Choose a gear before you start across.
Wrong choices
- Shift up halfway across to clear faster: A missed shift could leave you stalled on the tracks.
- Shift into neutral and coast across: Coasting gives you less control.
Question 2. Your vehicle gets stuck on the railroad tracks. What should you do first?
- ① Stay in the cab and keep trying to start the engine
- ② Get out of the vehicle and away from the tracks
- ③ Walk along the tracks toward the train to warn it
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Answer: ② Get out of the vehicle and away from the tracks
Key point: Stuck on tracks: get out and away, then call
If you get stuck on the tracks, get out of the vehicle and away from the tracks right away. Then look for the emergency number on the signpost or signal housing, or call 911, and give the crossing's location (and the DOT number if posted).
Wrong choices
- Stay in the cab and keep trying to start the engine: If a train comes, you could be killed.
- Walk along the tracks toward the train to warn it: This puts you in danger. Use the emergency number instead.
Question 3. What is your main way to control speed on a long, steep downgrade?
- ① Light, steady pressure on the service brakes all the way down
- ② Shifting to neutral to let the vehicle roll
- ③ The braking effect of the engine in a low gear
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Answer: ③ The braking effect of the engine in a low gear
Key point: Engine braking controls downhill speed
Use the braking effect of the engine as your main way to control speed on a downgrade. It is strongest in lower gears near governed rpm. Save your brakes for when you need to slow or stop.
Wrong choices
- Light, steady pressure on the service brakes all the way down: This overheats the brakes and can cause brake fade.
- Shifting to neutral to let the vehicle roll: Neutral gives you no engine braking at all.