The safety valve will still be functional and subject to the same pressure. The pickup point for the blast may also be under water! The firebed will also be upset and only subject to top air and none through the grate. All conjecture of course.

Since explosions in model boilers are exceedingly rare anyway, I don't think there is a great deal to be concerned about.

The only actual explosion in a model boiler that I have ever found out about was a model liner that blew up and sank about 1909. It would be fair to say that the construction of that boiler was somewhat deficient, to put it mildly. There was more recently (well, within the last 40-50 years…) a model loco boiler written up in ME that failed (but not explosively) due to being totally choked up with lime.

So provided the boiler is made properly to the relevant standard, and inspected regularly, there would seem to be very little risk. I suspect there is far more risk to the passengers and by standers from the actual derailment, eg broken arms and the like from the fall if the trollies go over too.

John

If full size is anything like scale models you quickly realise that if the blower is closed and the engine isnt moving the fire very rapidly fades to nothing. There was a model boiler explosion in quite recent times which caused at least one fatality…..but my memory fails me sat this point. I do remember that both of its safety valves had been hammered shut!

I believe that's probably a journalist that lacks a full understanding of how the boiler in a loco works. I do notice the boiler has failed at one of its weakest points, the end. The tube of the boiler remaining intact.

Dunno,

But the majority of those tubes look as though they are bent back on themselves, could they be superheaters ?