• Canadian National straight air system simmilar to an old brake system used in Sweden and Norway?

  • General discussion about locomotives, rolling stock, and equipment
General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

  by bengt
 
From about 1910 to 1988 a "Help Brakepipe System " were in use in Sweden and Norway for heavy trains on steep grades.

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Was the Swedish/Norwegian system simmilar to the system in use today by Canadian National?

"This straight air system, similar to using retainers on each freight car, is designed to hold a brake set and is controlled via an additional brake level in the locomotive cab. This allows the engineer to release and recharge the automatic brake system while descending a grade. Canadian National has a small fleet of specially equipped C40-8s, SD40-2s, and SD40-3s modified with straight air that are captive to this region."

Are there any Photos of the brake hoses and a sketch of the Canadian National system?

https://www.trains.com/trn/train-basics ... 8708701J3W
  by Pneudyne
 
My understanding of the Swedish system was that it was effectively a remote retainer system. That is, the individual wagon brake cylinder exhausts from their triple valves went not to atmosphere but to the additional pipe, whose release to atmosphere was controlled by the locomotive driver. Thus, the wagon brakes could be retained whilst the main air brake line was recharged. There was a brief description at the end of a Railway Gazette 1958 August 01 article on the SJ Dm class single-phase locomotives.

I do not know what system is used in Canada. In Australia, there was some application of straight air brakes to locomotives hauling iron ore trains. In this case there was an additional “wagon brake” control in the locomotive, and an additional straight air brake pipe that went to the wagons. This though seems to have been used more to provide better control during wagon unloading operations than for long downhill running out on the line. In the latter case, a straight air brake application would be slow to propagate down a long train. But if it were applied after the automatic brake, essentially to hold an existing application, that would be less of an issue.


Cheers,