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Efficient loading of intermodal container trains

National Rail Corporation

Industry contact: Gary Alexander (alexanderg@nrc.com.au)

MISG moderators:
National Rail Corporation A loaded container train is a heterogeneous entity, and the loading of this type of train presents itself as a stacking problem.

The objective is to maximise the load on each wagon (minimise the number of wagons for a given load), whilst incurring the minimum cost to the terminal operator and minimum delay to trucks which wait for containers to be unloaded and/or loaded.

A typical train is composed of a variety of wagon types and a variety of container characteristics, with up to 150 containers. A full train may have a nominal 8 hours in which to unload the incoming containers and load the outgoing containers, both activities being able to occur in parallel, and with several part and full-train loads being worked simultaneously in a terminal using common lifting equipment and labour.

Wagons are typically:

Length 12.2, 14.6, or 20.0 m
Deck height Standard, or well which allows full double stacking
Load capacity Various mass limit (depending on structural or axle constraints)

Containers:

Length 6.1, 12.2, or 14.6 m
Height Various, some of which can be double stacked.
Type Various, some of which can be double stacked.
Mass Distributed between 2 to 35 tonnes.

All container specifications are described at the time of booking, providing an opportunity to prepare a load plan that allows the dimensional and mass characteristics of the booked loads to be fitted onto the available wagons.

It is not appropriate to operate to a definitive load plan in which all containers are allocated specific slots on specific wagons.

  • Container mass can vary significantly from the mass nominated at the time of booking.
  • The lifting equipment may not be operating near the nominated slot when the container arrives in the terminal, and travel time along a section of train up to 1,500 m long may be an excessive loss of productive lifting time.
  • Trucks may have multiple loads to drop off and collect.
  • Containers nominated for double stacking may arrive in reverse order.

It is envisaged that one solution may be to develop a load profile based on historical data and actual bookings. MISG may provide insight into developing a load profile, or may provide other solutions.

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