During Channel Tunnel operation, airflows pass through the Pressure Relief Ducts from one running tunnel to the other. These can be substantial and impinge on the side of passing trains. Concern had been expressed about the adverse effects that this could have on certain types of less robust freight wagons, for example, curtain-sided and other types of swap body containers.

In order to assess the consequences of such flows on the design integrity of these structures, a train consisting of a selection of these wagons and containers was subjected to a simulation of the PRD exhaust flow by running the train through the efflux of a jet engine. The test was carried out in the open-air and was intended only to simulate the consequences of the direct impingement of the PRD flow.

The test train consisted of a class 47 loco hauling a train of the following BR and SNCF vehicles

1/ ANF Porte Autos car carrier with a small saloon car on the upper deck and alarger estate car on the lower deck

2/  20ft steel sided container with Twist Locks on a BR flat wagon

3/  40ft curtain sided container with Twist Locks on a BR flat wagon

4/ Cargowagon with sliding roof and sides on rails

5/ Debach type RFS curtain hooded steel coil carrier

6A/ 20ft steel sided container with UIC spigots on Ferry wagon

6B/ Savoyarde type TIP swap-body on Ferry wagon

In addition Lab Coach 15 Argus housed the instrumentation

The train was allowed to run up to 60 mile/h

Click on the picture for a bigger image all photos BR Official except where indicated.

It was concluded that further test were required and that future designs of similar vehicles should also be tested. Swap bodied and curtain sided vehicles should not be run through the Tunnel nor should open sided car carriers