Big Boy Locomotive Came to Nor Cal.

vavavroom said:
Is Big Boy going to be assisted by a diesel locomotive? I think that's usually the case because the infrastructure for supplying a steam.locomotive is lacking. It also saves wear and tear on the valuable Big Boy.
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In theory they now have the ability to run the steamer on the mainline without the diesel, having recently equipped it (the Big Boy) with Positive Train Control, but it is assumed it will continue to run with the diesel helper just in case of mechanical issues and/or to maintain track speed with the heavy train.

(Positive Train Control is the new system that can automatically stop the train in case it runs past a stop signal, or goes beyond the limits of its authority. Apparently they had to do a lot of special wiring and whatever else and mount it all in a cabinet in the tender, to make it happen)
 
UncleDave said:
Union Pacific's 4014 4-8-8-4 the mighty " Big Boy"

We chased it around for a day or so and had great fun.

What a beast. I can only imagine this thing hitting 103 on the open prairie.

It was 107 in Oroville that day, but we snuck down to get a shot of it over the bridge and when it pulled into the station.

With a plaque on the side stating it was made by THE AMERICAN LOCOMOTIVE COMPANY, and flags in front it couldn't be any more patriotic.

The sound - glorious is the only word I can use. Even sitting still it was like a thoroughbred making fluttering noise like a living creature.

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Almost as large, and equally impressive, with unique features, is the Cab Forward:


https://en.wikipedia.org/wiki/Southern_Pacific_4294

On display in Sacramento.
 
vavavroom said:
Here's the Backward or Cab Forward. Built in 1944.



Some of the Byzantine controls.
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Great for forward visibility and smokey tunnels.

Not so good for protection in grade crossing or other collision incidents.
 
Unfortunately I only managed to catch the loco today in Villa Grove, IL. I spent the day chasing through central IL, but was always a few minutes behind. Nokomis was the scheduled 3:00-3:30 stop, but I got stuck in stopped traffic outside Nokomis, was still there at 3:25, and knew I needed to be home by 5:00 so I just turned around and headed home.

Seeing it leave Villa Grove was a real treat, though
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PF52 said:
In theory they now have the ability to run the steamer on the mainline without the diesel, having recently equipped it (the Big Boy) with Positive Train Control, but it is assumed it will continue to run with the diesel helper just in case of mechanical issues and/or to maintain track speed with the heavy train.

(Positive Train Control is the new system that can automatically stop the train in case it runs past a stop signal, or goes beyond the limits of its authority. Apparently they had to do a lot of special wiring and whatever else and mount it all in a cabinet in the tender, to make it happen)
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It's also there to help with braking - I read somewhere that the Big Boy's brakes are custom made now so you don't want to wear them out any quicker than you have to.

It visited my neck of the woods Sunday/Monday only I couldn't get out to see it personally. Thank goodness for FaceBook and people posting tons of videos and pictures.
 
opus1 said:
It's also there to help with braking - I read somewhere that the Big Boy's brakes are custom made now so you don't want to wear them out any quicker than you have to.
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That doesn’t feel quite right to me.

I don’t doubt the custom made part-these days pretty much anything on a steam loco is “custom made”.

With that said, on mainline American rail(and most of the world now for that matter) the locomotive’s brake shoes are pretty insignificant in the overall braking of the train. The brakes on each individual car are far more important.

For a prime example of this, see the story of the train that crashed through the floor of Washington, DC Union Station back in the 50s. Basically on the ~20 car train, someone in the yard had failed to open the air cock on the connection between the 4th and 5th car. The engineer noticed something was off when he applied a small amount of brake and it made no difference in speed. With the train at full emergency(I have it in the back of my head that PRR and most other railroads ran 110psi on passenger trains, not the normal 90psi of freight), which means no pressure in the brake line and as much available pressure on the brake shoes, the loco+four cars couldn’t bring the train to a stop before the end of the platform. Fortunately there were no serious injuries from that one. The locomotive, a GG-1 electric, was cut in pieces for removal, put back together in Altoona, and survives to this day in preservation.

Air compressor capacity can limit sustained braking and recovery on a big train, but the Big Boy was also built to haul 100 coal hoppers over the mountains. It has two big compressors right up front(they were making their presence known) so that wouldn’t be an issue. I doubt a single SD70ACE, what they had as part of this train, adds much compressor capacity.
 
bunnspecial said:
That doesn’t feel quite right to me.

I don’t doubt the custom made part-these days pretty much anything on a steam loco is “custom made”.

With that said, on mainline American rail(and most of the world now for that matter) the locomotive’s brake shoes are pretty insignificant in the overall braking of the train. The brakes on each individual car are far more important.

For a prime example of this, see the story of the train that crashed through the floor of Washington, DC Union Station back in the 50s. Basically on the ~20 car train, someone in the yard had failed to open the air cock on the connection between the 4th and 5th car. The engineer noticed something was off when he applied a small amount of brake and it made no difference in speed. With the train at full emergency(I have it in the back of my head that PRR and most other railroads ran 110psi on passenger trains, not the normal 90psi of freight), which means no pressure in the brake line and as much available pressure on the brake shoes, the loco+four cars couldn’t bring the train to a stop before the end of the platform. Fortunately there were no serious injuries from that one. The locomotive, a GG-1 electric, was cut in pieces for removal, put back together in Altoona, and survives to this day in preservation.

Air compressor capacity can limit sustained braking and recovery on a big train, but the Big Boy was also built to haul 100 coal hoppers over the mountains. It has two big compressors right up front(they were making their presence known) so that wouldn’t be an issue. I doubt a single SD70ACE, what they had as part of this train, adds much compressor capacity.
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It is not the entire reason, but it is part of the reason.

Big Boy Info
 
opus1 said:
It is not the entire reason, but it is part of the reason.

Big Boy Info
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Dynamic braking-which is what that link is talking about- is a bit of a different beast, and yes it's something that no steam locomotive(at least that I'm aware of) has.

With that said, its main use is controlling speed downhill, or general speed reduction. Dynamic braking is definitely a good thing(it's how electric cars can drive with one pedal, although in trains it goes to a resistance grid and not into batteries) but it's a drop in the bucket compared to what the service air brakes can do.

So it is an explanation, and in mountainous areas especially dynamic breaking is a big deal for diesel power as compared to steam. Again, though, I don't see it as a huge benefit, but definitely one that the crew probably uses as appropriate. I doubt that coming through dead-flat central Illinois yesterday, the dynamic breaks had much if any use.

If Ross Rowland's dead-end ACE 3000 project had come to fruition, I'd have been curious if they'd incorporated and used dynamic brakes. On one hand, in a steam engine, I could see the waste heat from the resistor grid being dumped back into the boiler for later use. On the other hand, you'd be dumping it in during a period of low steam demand, and I could see a lot it still getting dumped out the safety valve(and as best as I remember, one of Rowland's big goals in that project was to use coal, which requires a lot of thinking ahead about fire size and it can't be reduced in a hurry like with oil) so that could also be complexity with no benefit. And I'm really pulling that out of my rear end-I have no idea if dynamic breaking in steak was ever discussed.
 
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