What's happening here?

[Raul_Duke]

I found this uncaptioned picture of what I think is "Duke of Gloucester," but what's that on the front please?


http://s30.postimg.org/psbieit9d/image.jpg

 

[Elecman]

It's a protective shield for staff when the engine was on running trials

 

[Johnuk123]

They were officially called Indicator Shelters and engineers would ride inside and take measurements of various things. They could check the expansion of steam in the cylinders and data on the smoke box for instance.
The engine would more often than not be pulling a dynamometer car for more involved tests.

Here's a couple of pictures.

[SIZE=-1] [/SIZE]

 

[edwin_m]

It's a protective shield for staff when the engine was on running trials

Specifically to obtain what were known as "indicator diagrams" to show the relationship between steam pressure and piston position in the cylinders.

https://en.wikipedia.org/wiki/Pressure_volume_diagram

 

[Taunton]

There's actually a man inside there, looking at instruments which were plotting on graph paper various details of how the cylinders were working. From these the calibration of the valves could be carried out. They typically seemed to appear on trials of a new class of loco.

Apart from avoiding claustrophobia and letting the operator see where they were, I'm not sure what part the small windows they always had in the front played.

 

[Steveman]

There's actually a man inside there, looking at instruments which were plotting on graph paper various details of how the cylinders were working. From these the calibration of the valves could be carried out. They typically seemed to appear on trials of a new class of loco.

Apart from avoiding claustrophobia and letting the operator see where they were, I'm not sure what part the small windows they always had in the front played.

Wouldn't they simply have been so the guys had an idea where they were so knew when a climb was coming up for instance.

 

[w0033944]

Apart from avoiding claustrophobia and letting the operator see where they were, I'm not sure what part the small windows they always had in the front played.

Might they have been primarily for the purposes of illumination (presuming that such trials only took place during daylight)? Without them, I'd imagine that it would have been pretty gloomy on all but the brightest days, which would have made reading values from charts and note-taking somewhat awkward.