Steam Locomotive Boiler Parts

[grumpyxch]

I've been reading a book on the history of the Stanier 3-cyl 2-6-4t locomotives, and in part of it, it tells of the modifications that were needed to the boilers in the early days. It started me thinking. They talk about boiler barrels, fireboxes, fire tubes, superheater elements and so on, but they never seem to name some parts. Therefore, I ask the forum what are the following called:-
1. The plate at the front that holds the ends of the fire tubes, superheaters, etc?
2. The front plate of the firebox that holds the rear ends of the fire tubes?
3. The rear plate of the firebox that is inside the water jacket?
4. The plate across the back of the boiler that has the firebox door, the guages etc mounted on it?

And finally what is the firebox wrapper - is it the sides and top of the actual firebox, or is it the part of the boiler barrel which covers the firebox (with water between them)?
Thanks very much

 

[John Webb]

1. Smokebox Tube Plate
2. Firebox Tube Plate
3. (not certain on this one!)
4. Backplate

The firebox wrapper is the non-cylindrical part of the boiler that contains the firebox. There are numerous stays between the wrapper and the sides and the crown (top) of the firebox; also between the backplate and the rear of the firebox.

There are several books available, including "Handbook for Railway Steam Locomotive Enginemen" (published in 1957 by BR and more recent reprints by Ian Allan from 1977 onwards), which detail the parts of a locomotive.

 

[grumpyxch]

1. Smokebox Tube Plate
2. Firebox Tube Plate
3. (not certain on this one!)
4. Backplate

The firebox wrapper is the non-cylindrical part of the boiler that contains the firebox. There are numerous stays between the wrapper and the sides and the crown (top) of the firebox; also between the backplate and the rear of the firebox.

There are several books available, including "Handbook for Railway Steam Locomotive Enginemen" (published in 1957 by BR and more recent reprints by Ian Allan from 1977 onwards), which detail the parts of a locomotive.

Thankyou John

 

[Taunton]

4. The plate across the back of the boiler that has the firebox door, the gauges etc mounted on it?

I'm pretty sure that old enginemen at Taunton called it the BackHEAD.

An amusing account (reprinted in 'The Railway Lover's Companion') is of a couple of soldiers in WW2 in Greece who commandeered a steam locomotive and its trainload of petrol. Never having been on a loco before, despite which they did quite well, they referred to this part of their steed as the 'dashboard', adding that this was probably the wrong word for it!

 

[grumpyxch]

I'm pretty sure that old enginemen at Taunton called it the BackHEAD.

An amusing account (reprinted in 'The Railway Lover's Companion') is of a couple of soldiers in WW2 in Greece who commandeered a steam locomotive and its trainload of petrol. Never having been on a loco before, despite which they did quite well, they referred to this part of their steed as the 'dashboard', adding that this was probably the wrong word for it!

Backhead rings a bell with me, but that name may be used by more than just GWR.

A new name that has come up in the book that caused this post is Throatplate. I'm assuming that is another name for No 2 (Firebox Tube Plate according to John). Now I'm not saying John was wrong. Perhaps different railway companies had different names for the same part. On the other hand, maybe my assumption is wrong.

Cheers. Have a good New Year

 

[Mcr Warrior]

A related query...

1501 failed early wednesday morning with the leaky fusible plug.

What exactly is a "fusible plug" (mentioned in the above extract which was taken from post #12 in the below-linked thread), where are such plugs normally to be found on a steam locomotive, and how, in simple terms, do they work?

Quick query - Severn Valley Railway

Is this railway only pre-book at the moment or can you turn up on the day. There seems to be nothing available tomorrow (Thu 28th). Thanks in anticipation.

www.railforums.co.uk

 

[Elecman]

A related query...



What exactly is a "fusible plug" (mentioned in the above extract which was taken from post #12 in the below-linked thread), where are such plugs normally to be found on a steam locomotive, and how, in simple terms, do they work?

Quick query - Severn Valley Railway

Is this railway only pre-book at the moment or can you turn up on the day. There seems to be nothing available tomorrow (Thu 28th). Thanks in anticipation.

www.railforums.co.uk

A fusible plug(s) is fittted to the top of the firebox (the crown) and will melt and allow steam/boillng water to enter the firebox if the fireman allows the water level in the boiler to drop below the top of the firebox crown as a warning of the lack of water. Very difficult to see this escaping steam/water jet however in a large very hot firebox

 

[John Webb]

A fusible plug(s) is fittted to the top of the firebox (the crown) and will melt and allow steam/boillng water to enter the firebox if the fireman allows the water level in the boiler to drop below the top of the firebox crown as a warning of the lack of water. Very difficult to see this escaping steam/water jet however in a large very hot firebox

The plug contains lead blocking a hole - with water on top of the plug the lead does not get hot enough to melt. If the water level is too low, the lead is no longer kept cool and melts. It may be difficult to see the jet of escaping steam, but it will be audible, and as the steam displaces the fire gases there may be flames pushed out of the firedoor. In addition as the steam displaces oxygen in the fire box, the fire will be affected and its burning rate reduced so the crew will notice also a drop in pressure as a result.

Backhead rings a bell with me, but that name may be used by more than just GWR.

A new name that has come up in the book that caused this post is Throatplate. I'm assuming that is another name for No 2 (Firebox Tube Plate according to John). Now I'm not saying John was wrong. Perhaps different railway companies had different names for the same part. On the other hand, maybe my assumption is wrong.

As the book I mentioned above was written to give a standard level of information to BR drivers, I assume that's what BR decided was their preferred names for the various parts of the loco.

 

[krus_aragon]

What exactly is a "fusible plug" (mentioned in the above extract which was taken from post #12 in the below-linked thread), where are such plugs normally to be found

It's operating principle is similar to the fusible wire (or fuses) that we use in electronic appliances: they're a sacrificial component that overheats (due to lack of water or excess current), melts, and stops any damage to the rest of the system.

 

[grumpyxch]

If the fusible plug melts, what do the footplate men do? I assume they would need to drop the fire quickly, but can they do that without opening the firebox door? If they open the door, would they not be scalded by the steam leaking into the firebox? Would the steam leaking into the firebox extinguish the fire and bring the temperature down enough to prevent further damage to the loco? Did all steam locos have a method of emptying the grate and ashpan quickly without opening the door?

 

[John Webb]

If the fusible plug melts, what do the footplate men do? I assume they would need to drop the fire quickly, but can they do that without opening the firebox door? If they open the door, would they not be scalded by the steam leaking into the firebox? Would the steam leaking into the firebox extinguish the fire and bring the temperature down enough to prevent further damage to the loco? Did all steam locos have a method of emptying the grate and ashpan quickly without opening the door?

Don't forget there is still a fair amount of heat promoting a flow of combustion products away from the firebox through the boiler tubes so some part of the steam from the fusible plug will be drawn out of the firebox; the position of the firebox door will also help to encourage fresh air to flow into the box rather than allowing steam out. It should also be born in mind that generally the crew will be aware of the possibility of the fusible plug operating and will have started taking action to reduce the fire size. (For example: if both injectors have packed up and they can't get water into the boiler.)
Some grates, particularly on the BR Standard classes and other recent designs of locos had 'rocking grates' - the fire bars could be partly turned remotely and thus operated to dump the fire into the ashpan. Otherwise it was a case of using the shovel to remove the fire from the firebox and throwing it off the footplate.