Capuchon (chimney)

[1] Sometimes capuchons were made of plate steel bolted or welded in place, others were an integral part of the chimney casting.

A moving locomotive can suffer problem downdraughts when air flowing over the chimney is diverted down it on meeting the back rim.

Capuchons were initially added to raise the stream of air slightly so it would clear the back rim, thereby preventing the downdraught.

A capuchon alone was no longer enough to keep the smoke clear of them, and additional measures were needed: for example, the use of large metal plates to affect airflow.

[1] Many Belgian locomotives built in the late 19th and early 20th centuries were fitted with distinctive high capuchons, for example the Type 8 4-6-0 compounds.