A few summers back I had the pleasure of riding behind (or before?) one of Mount Washington's impressive little steamers to the summit. During our layover I conversed with the crew and asked why the boilers on rack locomotives are often angled forward instead of the standard horizontal position. I was told that this is done to keep the water level when ascending and descending the steep grade. It wasn't until much later did I ask myself what happens on the fairly level sections of track at the very top and bottom.

How does the crown sheet stay covered when the locomotive is no longer on the grade and the boiler is angled forward?

I've never fired one (few have) but I'm guessing the fairly short length of the boiler allows them to keep the crown sheet covered even when on the fairly level track. When working hard, having it become level helps prevent "working water". The tall steam dome also helps.

The cog boilers are mounted at an angle of 25%. This is the average grade of the line. When they are on the steepest section of line (Jacobs ladder) they are at 37 %. There is a flat section at the shops.

The original boilers where vertical to allow for the grades. Trunnions where fitted so the boiler remained vertical. I guess that they where a standard stationary boiler converted for this use.

As the loco's got bigger the switched to horizontal boilers. It is true that they are short and the tubes are very short of a big diameter and small total gas flow area. The gauge glasses are mounted on the back head they are very tall, about 18 inches or more to give the full range of grades. Later practice on other railways was to put the gauge glass on the centre line of the boiler so to give the average reading of water level. The crews of the cog have to learn the water level for each grade on the railway. There are test cocks as well.

On the steepest grades the tubes at the top front are nearly exposed whilst at the rear the water is up to the top of the barrel and out of sight in the gauge glass. As you come off the steep grades you water level will drop at the rear dramatically so you have to make sure you carry enough water.

On the flats (leveller) places the top of the firebox would be exposed except for the fact that the top is slopped down from the tube plate to the back head. Here the gauge glass will show just an inch or two of water.

Other features like the tall dome do help and like when the Snowdon engines where built they had to replace the dome with a higher one.

it may depend how hot your fire is, you might not melt it or warp it like on standard steamers.

All the standard rules apply and there are fusible lead filled plugs so the above is not valid.

If you have any questions about the heat of the fire on a cog locomotive, check this out. http://youtu.be/0z8sNTbMPNc

The term "blast furnace" comes to my mind.

Roger

Impressive video! Roger, was the ride up on #9, or were they just showing it coming into the station?

The video indicates late 2008, when the line still had 6 engines that could operate. The cab ride/firing exercise appears to be on board the 4/8 lash-up. Apparently, the 8 had failed a boiler inspection a season or two earlier and it was retired. The cab and tender of 8 was mated with the boiler/chassis of the 4 and that really beat-up-looking lash-up ran until regular hourly steam ceased in roughly June of 2009. The scenes with the gentleman trying his hand at firing appear to have been shot from Skyline Siding up into the homestretch flats.

The word blowtorch is an apt description for the firebox on one of those cog engines. The draft is unbelievable. Numerous times, I was on the mountain taking photos and felt the rain of cinders that continued for several seconds after the train passed me.

God, I miss that. It was just cool. Too bad they had to pretty much quit doing it during my lifetime. :o(

/Kevin

Hugh,

It's not my video and I think Kevin nailed the facts. The roar from the firebox is most impressive. I wonder what percent of coal goes out the stack I burned?

It is a shame they have almost completely dieselized. There were not many places in the US, or the world, where you could regularly see 5 or more locomotives in steam in one place. On the upside, they seem committed to running the first trip a day as steam.

Roger

For those who never had a chance to see The Cog when steam ruled the mountain, you can go to this link and see some photos that I shot during 2008 and 2009. It took some serious hiking, but I could see the end coming, and I knew I would never regret my time on "The Rockpile".

http://www.railpictures.net/album/26/

/Kevin

Note today's satellite photo shows the coal pile and coal lift are gone.

Somewhat OT-I suspect that that is an indicator of a coming long term trend. I converse regularly with my late second cousin's husband who has spent his entire career as a scientist working on coal-specifically developing new uses for coal and related byproducts as fuels and chemicals. The smart producers are concluding that in the long term-50 to 70 years, coal will become a niche fuel in the form that we know it as. Some producers are now carefully examining ways to break coal down into its basic elements so that it can be used for chemical production. The profitable energy companies will be those that break away from the single product model and expand their energy product offerings.

Note today's satellite photo shows the coal pile and coal lift are gone.

They now have coal stockpiled against the wall in what I believe is the employees parking lot and they load with a front end loader. Also recently torn down is a large wooden structure opposite side of the tracks and just South of where the old coal tipple was. Not sure what it was used for but it had been there forever.

The coal Shute was falling part in 2007. I am surprised it lasted even a few years after.

Not sure which structure you mean. Right next to the coal and ash pit was a small shack for storing loco supplies.

Down near the shops some of the cabins have been flattened.

Behind the water tank and next to the river was a pump house. Don't know if that's there still. It was for snow making.

That makes a lot of sense, thank you for the very comprehensive answer.

I know this is a bit of a stretch, but do any online scans exist of the blueprints to a cog steamer? I'd be very interested in seeing the design of the firebox and the placement of the flues.