Train brakes for the little Mogul

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Raymbo
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Re: Train brakes for the little Mogul

Postby Raymbo » Thu Dec 07, 2017 11:43 am

The brake rigging on this little Mogul already has equalization in them, the original builder must have done this. They are very efficient but train brakes are still needed because the drivers on the engine will slide on a grade trying to slow or stop a train.
Ray Grosser

Former
US Navy Sea Bee, 50s
Journeyman T&D maker, 60s
Builder 1" scale 4-6-2 Little Engines locomotive 63-65
Machinist on the Great Northern RR
Certified welder
Steel erection superintendent
US Army paratrooper, 11SFGP ABN
Taylor 12 string guitar picker
Harley owner and rider
Now that I think of it, I might have made something of myself.


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johnpenn74
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Re: Train brakes for the little Mogul

Postby johnpenn74 » Sat Dec 09, 2017 9:21 pm

Something is not right. If the wheels are locking up then something isn't free in the rigging or the steam application is just to much. Any idea how much pressure is being sent?

I will argue that when your brakes work correctly, you can lock the engine down even at full throttle, and you will be able to stop without skidding.

I am not a big fan on the aforementioned brake redesign as it requires a lot of new parts, specifically the beams. You can solve this equalization problem by just buying the right size clevises that overlap the existing Allen brake beams (per the prototype), not through the beams.

I believe that this design has obstruction issues with the below frame suspension. Or perhaps a bind from beam rotation of the pull rods through the slot. Dragging on the leafs, this is what we noticed on Rodney's engine. Still haven't figured out why his isn't working right.

I could make a lot of claims on what I got to work, but I guess that's not really going to help. So I'll just leave it at, something is amiss in your set up, I believe you can resolve it with a little more work.

JP
John Pennington

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johnpenn74
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Re: Train brakes for the little Mogul

Postby johnpenn74 » Sat Dec 09, 2017 9:22 pm

I cam curious to see what the arrangement is like, can you post a picture from the bottom side of the brakes beams?
JP
John Pennington

Project
2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars <--ALMOST DONE!!!!
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars <--ALMOST DONE!!!!
L&N Caboose
4 Big Four Conversion Gondolas
A whole pile of incomplete stuff...
Like I'm actually gonna build all this stuff :-P

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Raymbo
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Re: Train brakes for the little Mogul

Postby Raymbo » Sun Dec 10, 2017 6:03 am

The reason the engine will skid on a hill is because the train weight is more than the engine itself, it is the train pushing the engine. Running light it will stop without problems and the brakes are working as designed. Just like the prototype on many roads, the Soo Line and the L&N, these Moguls were light on their feet. This little engine will pull a fair amount of train, especially on a flat track. https://www.youtube.com/watch?v=zjEt9n8g6r4

In this video I made an error in going up the hill. I slacked off on the throttle in an attempt to show it could start the train on a hill. It pulled the train up in the end. Going down a similar hill it is absolutely necessary to use the train brakes to keep from running way too fast. While the engine brakes will slow it down, it is more difficult to control as the steam brakes are either on or off. Attempting to use just engine brakes in this way is not efficient so the train brakes are used.

All in all, I don't think there is anything wrong with the set up on the engine, it is just too light to hold a heavy train on a hill.

RG
Ray Grosser

Former
US Navy Sea Bee, 50s
Journeyman T&D maker, 60s
Builder 1" scale 4-6-2 Little Engines locomotive 63-65
Machinist on the Great Northern RR
Certified welder
Steel erection superintendent
US Army paratrooper, 11SFGP ABN
Taylor 12 string guitar picker
Harley owner and rider
Now that I think of it, I might have made something of myself.


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makinsmoke
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Re: Train brakes for the little Mogul

Postby makinsmoke » Sun Dec 10, 2017 9:15 am

I would think with a train attached you would use train brakes, and engine brakes when running light.

Not sure of the advantages of using the engine brake only when trying to stop or slow your train.

Maybe I'm misunderstanding something.

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BigDumbDinosaur
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Re: Train brakes for the little Mogul

Postby BigDumbDinosaur » Sun Dec 10, 2017 10:46 am

makinsmoke wrote:I would think with a train attached you would use train brakes, and engine brakes when running light.

That would be typical of full-sized practice. When making a brake pipe reduction, the engineer will usually bail off the independent brake, which means the train is slowing down the locomotive(s). This procedure tends to keep the slack stretched, preventing a run-in.
Science makes it known. Engineering makes it work.

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Raymbo
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Re: Train brakes for the little Mogul

Postby Raymbo » Sun Dec 10, 2017 12:31 pm

Precisely and what we normally do.
Ray Grosser

Former
US Navy Sea Bee, 50s
Journeyman T&D maker, 60s
Builder 1" scale 4-6-2 Little Engines locomotive 63-65
Machinist on the Great Northern RR
Certified welder
Steel erection superintendent
US Army paratrooper, 11SFGP ABN
Taylor 12 string guitar picker
Harley owner and rider
Now that I think of it, I might have made something of myself.


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johnpenn74
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Re: Train brakes for the little Mogul

Postby johnpenn74 » Thu Dec 14, 2017 11:36 pm

Ray,
Yes, absolutely, if you throw enough pressure against you brake cylinder (air or steam) you will lock it up and slide. Truthfully its more operator error than anything else. And yes air is much more forgiving than steam since steam is not regulated and has to be feathered in.

My point is if your brakes are not equalized you will put your self into a skid whole lot easier than if it is equalizing correctly. Its simply a matter of traction and friction. The adverse is also true in pulling power, if you wheels / suspension is equalized you will pull more because you are not burning applied force up as friction between the driver and rail on one of many drivers. The more equal weight on the wheels is the better it pulls. Those are reason why the prototype equalized the suspension and brakes.

If you haven't already, I'll suggest you put the loco brakes on air and see at what force things start skidding. It will be the same whether you have 1 car in tow or a mile in tow; as the engines weight and corresponding NuY doesn't change.

If the skid starts at really low pressure or happens at all kinds of different pressures then the equalizing in the brakes or suspension isn't doing its job. Whats happening is you are catching a single axle over the rest.

Sure, you going to use the train brake over the engine brakes in most cases. That is unless you don't have brakes on your cars which is a lot of people in this hobby or you are on a really long down grade and don't want to over heat the brake pads. In that case, put it in reverse, open the drains, open the throttle. Just like dynamics on a diesel.

JP
John Pennington

Project
2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars <--ALMOST DONE!!!!
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars <--ALMOST DONE!!!!
L&N Caboose
4 Big Four Conversion Gondolas
A whole pile of incomplete stuff...
Like I'm actually gonna build all this stuff :-P

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NP317
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Re: Train brakes for the little Mogul

Postby NP317 » Fri Dec 15, 2017 11:27 am

Another reason the prototype railroad steam engineers would release the engine brakes while applying the train brakes, was to prevent over-heating the locomotive's driver tires. These tires are heat-shrunk onto the drivers. Heat them too much and they will come off!
This happened mostly with tall-drivered fast locomotives.
There are very few photos available (I can't find any now) showing the results of this nasty situation. Some with OK results, others catastrophic!
~RN

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Greg_Lewis
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Re: Train brakes for the little Mogul

Postby Greg_Lewis » Fri Dec 15, 2017 12:07 pm

NP317 wrote:Another reason the prototype railroad steam engineers would release the engine brakes while applying the train brakes, was to prevent over-heating the locomotive's driver tires. These tires are heat-shrunk onto the drivers. Heat them too much and they will come off!
This happened mostly with tall-drivered fast locomotives.
There are very few photos available (I can't find any now) showing the results of this nasty situation. Some with OK results, others catastrophic!
~RN


The cutline on this one says he's standing calmly, but since the tire came off at 70 m.p.h. I wouldn't be surprised if he had to buy a new pair of overalls.


IMG_7251.JPG
Greg Lewis, Prop.
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ccvstmr
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Re: Train brakes for the little Mogul

Postby ccvstmr » Fri Dec 15, 2017 12:20 pm

...looks like a photo out of Reed's book of Train Wrecks. Although I'd have to say, if the loco was doing 70 mph...I doubt very much the engineer had his hand on the brake lever BEFORE the tire came loose. Therefore, heat from braking might not have been a factor. After the fact...no doubt, it was time to "retire"! Sorry...couldn't resist! Carl B.
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NP317
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Re: Train brakes for the little Mogul

Postby NP317 » Sat Dec 16, 2017 11:34 am

Greg:
That's one of the photos I was remembering! Thanks for dredging that up.
Frightening possibilities.

I was taught to fire and engineer steam locomotives by Jim Norvell, an old Great Northern Engineer.
He was pretty definite on how things should be done, and always explained the safety reason.
I consider myself very lucky to have experienced Jim as my teacher!
Happily, I've been assisting his namesake grandson with his 7.5" gauge live steamer and railroad pursuits.
~RN


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