Pilot Truck question


Roger Clay
 

What feels like a very novice question: Why do many MR steam locos have their pilot trucks attached to the frame in such an un-prototypical fashion. I'm guessing to make them less susceptible to derailing.

-- burnin' rio


Climax@...
 

In most cased model railroad radius is much shaper than prototype and the only way for a scale locomotive to stay on the tracks is to make the leading and trailing trucks more free to swing.

-----Original Message-----
From: Roger Clay
Sent: Feb 23, 2021 5:57 PM
To: HOn3@groups.io
Subject: [HOn3] Pilot Truck question

What feels like a very novice question: Why do many MR steam locos have their pilot trucks attached to the frame in such an un-prototypical fashion. I'm guessing to make them less susceptible to derailing.

-- burnin' rio


Roger Clay
 

Thank you. This is pretty much what I thought.

On Feb 23, 2021, at 7:13 PM, Climax@... <Climax@...> wrote:

In most cased model railroad radius is much shaper than prototype and the only way for a scale locomotive to stay on the tracks is to make the leading and trailing trucks more free to swing.



Roger Clay
The 7th Direction
Marin County, California
mobile & txt: 415-233-1290


Randy Hees
 

There are very few models which mount correctly.  And none I am aware of in HO(n3)...  We use too tight radius compared to the prototype.  Generally the prototype has equalization to transfer weight from the drivers to the lead truck, in some cases steering, and some 4 wheel trucks have swing motion.  

The key in model construction is finding a way to keep enough pressure via springs or weight on the truck to have it track well, and.flexible enough so it doesn't bind.  One option is a conical spring, particularly on a 4 wheel lead truck, likely with a slotted mount.   On a 2 wheel lead truck I am trying a flat spring, which pivots with the truck.

Randy

On Tue, Feb 23, 2021 at 7:13 PM <Climax@...> wrote:
In most cased model railroad radius is much shaper than prototype and the only way for a scale locomotive to stay on the tracks is to make the leading and trailing trucks more free to swing.

-----Original Message-----
From: Roger Clay
Sent: Feb 23, 2021 5:57 PM
To: HOn3@groups.io
Subject: [HOn3] Pilot Truck question

What feels like a very novice question: Why do many MR steam locos have their pilot trucks attached to the frame in such an un-prototypical fashion. I'm guessing to make them less susceptible to derailing.

-- burnin' rio


Jim Spencer
 

The problem with springs with lead trucks especially is they have the effect of “lifting” the front drivers off the rails, thereby reducing traction and increasing the likelihood of derailments thru picked points, etc.
I use a different approach: put a small lead weight on top or at the bottom of the truck. The added weight right over the wheels lessens the likelihood of a lead truck derailment while not affecting the weight on the drivers. Try it!


Bill Lugg
 

How much weight would you say you're adding to the truck to make it track correctly?

Thanks
Bill Lugg

On 2/24/21 4:50 PM, Jim Spencer wrote:
The problem with springs with lead trucks especially is they have the effect of “lifting” the front drivers off the rails, thereby reducing traction and increasing the likelihood of derailments thru picked points, etc.
I use a different approach: put a small lead weight on top or at the bottom of the truck. The added weight right over the wheels lessens the likelihood of a lead truck derailment while not affecting the weight on the drivers. Try it!


Steve Hatch
 

What ever will fit there.   You can't overload it since there isn't enough room.
The extra weight has no effect on the traction of the loco and it NEVER is enough
to cause a problem.
   Over the years I've discovered that just making sure the lead truck can swivel up down
and side to side as well as rock side to side is plenty with or without weight.
The weight does make it "better" but only if you've made sure of the complete articulation
of the truck.
Steve