How much does double-stacking save? - Trains Magazine

The big advantage of double stacking is in train length.

This is important on long single track lines.

In areas of limited clearances there are often double tracks which reduces the need for double stacking.

There are links to some videos of Cajon Pass where whole trains are shown.

Many of these are all double stack containers, but others are double stack leading trailer on flat car and single stack containers, just on this route on BNSF, which matches what I've seen.

I recognise your avatar as the steam "Spirit of Progress".

As you no doubt know, that line is to be modified for double stack for the Inland Rail line to Brisbane, which will be single track for most of its length.

That line to Sydney is double track north of Junee and between Albury and Seymour, so there is less need for double stacking. However, the Inland Rail section to Illabo is about half way to Sydney anyway....

In Australia, clearances and axle loads are not as favourable for double stacking as in the USA. Double stack wagons can't use articulated trucks between wells because the axle loads would exceed the allowable limit for high speed operation, but articulation is fine for single stack trains.

So the weight differential for double stack would be higher in Australia since each well has to have two trucks, even if they are in groups of five. There were five articulated well sets built in Australia for high cubic light weight traffic (like breakfast cereal boxes).

In Australia there are very few 53' containers, with 48' being the norm and most articulated sets are to this length. The RRYY and TRAY type flats with small diameter wheels can all carry 53' boxes, and were used with half height boxes double stacked west of Adelaide.

In the USA, clearances encouraged New York Central to go with Flexi-Vans rather than TOFC, and some well vehicles were equipped to carry trailers in the wells for similar service. The Road Railer vans were mainly used in the East, where clearances could be a problem.

CSX is working to improve clearances in Baltimore and Washington DC where tunnels run under the city.

So the answer about weight differential depends on the allowable axle load and the maximum weight of container to be carried. The differential would be less in the USA than in Australia.

Peter