When lining up to couple, where should you first stop the tractor?
Saskatchewan Commercial overview
Saskatchewan Commercial: Coupling, uncoupling and trains
Coupling and uncoupling a tractor-trailer with air ride suspension step by step, tug tests, landing gear, hooking up a pup-train and converter dolly, safety chains, draw-bar rules and breakaway brakes.
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- 14 questions
- Topic drill
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Study reference: SGI Professional Driver's Handbook (2026-27), Ch. 6 Information for Class 1 and Class 3 — Coupling, Uncoupling, Train or pup-train, Connecting vehicles
All 14 questions in this test
Every question and its answer choices. The correct answers and explanations appear when you take the test above.
When lining up to couple, where should you first stop the tractor?
- With the fifth wheel locked under the kingpin
- Fifth wheel just ahead of the trailer, off the kingpin
- About ten metres away, so you can walk around and inspect the trailer
- With the drive wheels under the trailer apron
Before backing under a trailer, how should the fifth wheel look?
- Dry, with all grease wiped off
- Slide pins pulled out and unlocked
- Horns tilted down and jaws unlocked (open)
- Horns tilted up and jaws locked
What must every trailer equipped with brakes have in case it breaks loose?
- A spare set of gladhands kept in a sealed box
- A second electrical cord as backup
- A reflector on the hitch tongue
- A device to apply its brakes automatically
With air ride suspension, what do you do with the tractor suspension as you back under the trailer?
- Dump it and leave it down while driving away from the yard
- Leave it unchanged the whole time
- Dump it, then restore normal height
- Raise it to the highest setting first
When uncoupling, at what point do you stop to dump the tractor air suspension?
- Before releasing the fifth-wheel lock
- Before lowering the landing gear
- After the tractor is fully clear of the trailer
- When the kingpin is just clear of the jaws
In a train, the rear trailer starts to fishtail. What does SGI recommend?
- Brake hard with the foot valve and steer away from the swing
- Steer sharply against the swing
- Lightly apply trailer brakes and add power
- Release power and coast to a stop
After you hear the fifth wheel lock, how should you confirm the coupling?
- Drive one block and then check it
- Rock the trailer with the landing gear
- Listen for the air dryer to purge
- Do at least two tug tests and look at the jaws
How should you attach the converter dolly tongue to the pintle hook?
- By leaving the safety latch open for turns
- By backing into it at speed
- By hand, then fasten the latch, chain and pin
- With the trailer hand valve applied
How should safety chains be attached between a converter dolly and the lead trailer?
- Crossed under the tongue
- Left hanging loose for turning
- Wrapped around the pintle hook
- Attached to the dolly axle only
When uncoupling, how far should you lower the landing gear?
- Until the trailer lifts fully clear of the fifth wheel plate
- Until the trailer is level with the dock
- Just until the pads touch the ground lightly
- Until most weight is off the tractor, trailer still on the fifth wheel
When a coupling device other than a fifth wheel is used, what else is needed?
- An auxiliary chain or cable as strong
- A red flag on the draw-bar
- An extra set of trailer mud flaps
- A second fifth wheel fitted to the front of the trailer
After connecting the air lines, how do you supply air to the trailer?
- Pull out the yellow parking brake valve
- Open the draincock on the trailer tank
- Apply the trailer hand valve fully
- Push in the red trailer supply valve
Apart from pole trailers, what is the maximum length of a draw-bar between a motor vehicle and trailer?
- 1.83 m (6 ft.)
- 4.6 m (15 ft.)
- 0.9 m (3 ft.)
- 3.05 m (10 ft.)
What is the last coupling step SGI lists before driving away?
- Pull ahead and test trailer brakes with the hand valve
- Release the tractor air suspension and leave it lowered
- Lower the landing gear back down to the ground for support
- Disconnect the electrical cord to test it
Coupling, uncoupling and trains: key rules to remember
Our summary of what the official handbook says on this topic, in our own words. Read it before or after the practice questions above, then check the original chapter. Read the official chapter ↗
Ch. 6 Coupling a tractor-trailer with air ride suspension (pp. 121–122)
- Inspect the area in front of the trailer, align the tractor and back slowly until the fifth wheel is just ahead of or slightly under the trailer, not against the kingpin.
- Tractor checks: air lines and cord secure, fifth-wheel horns tilted down, jaws open (unlocked), fifth wheel firmly mounted, slide pins locked, enough grease.
- Trailer checks: couplers undamaged, kingpin and apron not worn or cracked, kingpin lined up with the jaws, trailer height right for the fifth wheel, axle slide pins locked, trailer secured, cargo secure.
- Dump the tractor air suspension and back under the trailer, stopping before the kingpin; restore normal ride height; back slowly until the jaws lock.
- Do at least two tug tests and look to confirm the jaws are closed around the kingpin.
- Connect the electrical cord and check trailer lights; connect air lines; push in the red trailer supply button; check gauges and the hand valve.
- Make sure trailer air bags inflate, raise both landing gear legs and stow the handle.
- Drive ahead slowly and apply the trailer brakes with the hand valve; all trailer wheels should be turning before the test.
Uncoupling (p. 123)
- Choose level, firm ground; park in a straight line; chock trailer wheels if needed.
- Deflate trailer air bags; lower the landing gear (dolly pads if loaded or on poor ground) until most weight is off the tractor but the trailer still rests on the fifth wheel.
- Disconnect lines and stow them in the dead-end couplers.
- Unlock the fifth wheel, pull ahead until the kingpin clears the jaws, dump the air suspension, then pull ahead until the fifth wheel is out from under but the frame is still under the trailer.
- Confirm the landing gear and ground hold the trailer, then drive clear and restore ride height before leaving.
Train or pup-train and connecting vehicles (pp. 124–125)
- A train pulls another trailer behind the tractor-trailer using a converter dolly.
- Pull with steady power on straight stretches; if the rear trailer fishtails, apply trailer brakes lightly and increase power.
- Avoid sudden lane changes, sharp turns and speeds too fast for conditions.
- Check the rear hitch, safety catch, chains or cables, and that air lines between trailers do not sag.
- Hook-up order: park and brake the rear trailer, line up the dolly with its kingpin, couple tractor and lead trailer, back up to the dolly, inspect the hitch, hook the dolly tongue to the pintle hook by hand and fasten the latch, chain and safety pin.
- Cross the safety chains so a broken tongue is held off the road.
- Some companies colour-tape service and emergency lines on dollies to prevent mix-ups.
- Draw-bars must attach directly to the vehicle frame; any coupling other than a fifth wheel needs an auxiliary chain or cable of equal strength.
- Except for pole trailers, the draw-bar may not exceed 1.83 m (6 ft.).
- If a trailer whips or swerves, slow down and stop to find the cause.
- Trailers with brakes must have a device that applies them automatically if the trailer breaks away.
Study the Coupling, uncoupling and trains rules as flashcards →
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