Thanks for that Willis. The steel post has gone. I hadn't thought of a fan, but as I am getting rid of the smoke unit it should fit in there quite well and use the smoke unit wiring to power it. My problem is I want to use a visaton speaker which is 32mm high I am looking for a shoe horn to try to prise it in.
                               Later Ron.

Thanks JD. I thought I would ask the question before doing a search.  having just done a search the answer seems to be. It does nothing!
                           Later Ron. 

I am in the process of converting the 2-6-6-2 articulated loco to battery power.  In the front end of the boiler behind the smoke unit is a solid steel  post labelled on the parts diagram as part # MTG73 what is it ?, what does it do ?, can I remove it ?, as it is only held on by one screw
                                   Later.  Ron.