Lorry Loader Delivery onto a Mid-Levels Carriageway with an Overhead Line
A 6×2 lorry-mounted loader rated 8 tonne-metres, with a capacity of about 2.4 t at 4.5 m radius, is delivering six 2.1 t steel plates to a Mid-Levels site. The only stopping place is the near-side traffic lane. The pavement contains a cast-iron cellar hatch roughly 2.2 m from the kerb, exactly where the nearside outrigger would sit. An 11 kV overhead line crosses the road at about 6 m above the carriageway and the crane will need to boom out on that side to reach the site gate. The site's only other hardstanding is a steep access ramp. The driver is alone; the site can provide one labourer who "can wave him in". Traffic is single-lane alternating and the road occupancy permit runs 10:00–12:00; it is now 11:40. The plates are stacked with no packing between them, and one lifting eye is chipped.
1. Identify every condition that must be resolved before the first plate is lifted, and explain why each one matters rather than simply naming it.
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Ground and outriggers. A cast-iron hatch cover is not a load-bearing surface - it is a lid over a void. An outrigger float on it will either punch through or load the cover's frame unevenly, and the resulting settlement transfers load into the machine's stability margin while the plate is in the air. The outrigger needs a load-spreading pad on proven ground, or a different position, or the lift does not happen.
Overhead line. Booming out under an 11 kV line puts the boom, the hoist rope and the suspended plate into the approach distance. Electricity jumps; "we didn't touch it" is not a defence. The line must be isolated and proved dead by the utility, or the lift re-planned so the whole machine and load stay outside the safe clearance, with goalposts or barriers marking the limit. This is a decision for the utility and the site's competent person, not the driver.
Single-handed operation. A lorry loader on a live carriageway needs a banksman for the traffic interface and a separate person for the load - one labourer with a waving hand covers neither, and the driver cannot see the load, the outriggers and the traffic at once.
Rigging. No packing between plates means the stack can slide as each plate is drawn off, and the sling on the chipped eye can pull out under 2.1 t. Both are load-loss risks, not cosmetic defects.
Permit window. Twenty minutes is not enough for six plates with this many open items; overrunning puts a crane in a live lane outside the agreed control.
2. Assuming the overhead line can be isolated in time, set out the sequence for unloading the first plate.
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- Confirm the isolation in writing and confirm the permit window has been extended. If either is missing, do not start - the first plate is not worth a partial commitment.
- Position the vehicle so the minimum boom radius and tail swing are achieved, with the outriggers fully extended onto load-spreading pads on sound ground, clear of the hatch. Check the ground and the pads after loading and again during the lift.
- Set the traffic control first: cones, signage, a banksman at the traffic end, single-lane working as per the permit. The road is the first hazard the driver meets and the last one to be cleared.
- Stabilise the stack and inspect the rigging. Pack between plates, use a sling arrangement that shares the load, and reject the chipped eye - a plate with a defective lifting point is set aside, not "carefully" lifted.
- Confirm the radius and read the actual load chart for the boom length and radius being used, with the outriggers in the deployed configuration. 2.1 t at 4.5 m is close to the stated capacity; there is no margin for a longer radius.
- Lift, check, then transfer. Raise the plate just clear, hold, confirm stability and the sling seating, then slew slowly with a tag line. No one under the load, no one in the slew arc.
- Land and release, then re-check the outriggers before the next plate.
Repeat the chart and rigging checks for every plate - the second lift is where the discipline usually slips.
3. The driver cannot find the load chart and the plate positions are not marked, so the radius is a guess. What should happen, and why is estimating the radius from the ground unacceptable?
Read the worked answer
The lift stops. This is not a paperwork problem; it is the removal of the only means of knowing whether the machine can hold the load.
Why estimating is unacceptable:
- Capacity falls steeply with radius. On a lorry loader the capacity curve is not linear - a small increase in radius near the end of the chart can cost a large proportion of capacity. An error of half a metre at 4.5 m can put a 2.1 t plate beyond the rating.
- The chart is machine-and-configuration specific. Boom length, outrigger deployment, and whether the outriggers are fully or partially extended each change the permitted load. A number remembered from another truck, or from the delivery note, describes a different machine.
- The consequence is not a near-miss. Overload at radius on a lorry loader is a lorry on its side or a plate in the road; on a slope with a live carriageway, both outcomes involve people who never agreed to take the risk.
- Two unknowns compound. Unknown radius plus unknown chart is not "probably fine" - it is two independent uncertainties multiplied.
What should happen: the driver obtains the machine's own load chart and rating plate, marks the plate positions on the ground, measures the radii, and confirms the configuration against the chart. If the chart cannot be produced, the machine is not fit for the lift and the task is rescheduled - with the load left secured on the vehicle and the road reinstated.