richhotrain The one trouble with that test is that it does not account for a boiler and driver wheelsets that may not be in balance from front to rear. In my case, BLI long ago conceded that the boiler and driver wheel assembly was not balanced properly and that is why their solution is to add a stronger spring to the trailing truck to replace the weaker spring initially installed at the factory. They have reworked a large number of 2-10-2 and 2-10-4 steamers that have been returned to them for that reason. Rich
The one trouble with that test is that it does not account for a boiler and driver wheelsets that may not be in balance from front to rear. In my case, BLI long ago conceded that the boiler and driver wheel assembly was not balanced properly and that is why their solution is to add a stronger spring to the trailing truck to replace the weaker spring initially installed at the factory. They have reworked a large number of 2-10-2 and 2-10-4 steamers that have been returned to them for that reason.
Rich
Rich:
That balancing problem has been around for a long time. In my case, I've had to balance the weight in any number of my brass steamers, as the locos have come with the weight installed shoving the balance back toward the rear drivers and the firebox. I've had to unscrew the weight, push it forward and re-attach it so that the forward drivers are more in balance. Oddly enough, I've had less of a problem with this on the older Japanese brass than the newer Korean (which always seem to be a little underweighted to begin with). With the weight re-adjusted, and since the drivers are sprung to begin with, my large wheel-based non-articulateds seem to have no trouble on my trackwork.
On most of my steamers the 2-wheel lead truck is just "along for the ride" so to speak, very few of them are factory sprung. And as I've said, the several that I've had problems with have been cured by epoxying a bit of lead weight to the underside of the truck tongue. On 4-wheel lead trucks, the factory-installed springs seem to be sufficient, as the downward tension is just enough to keep them on the tracks, but not cause them to 'lift' against the drivers.
Of course, on my Yuba River Sub, because of grades and terrain, there is really no place on the layout where I can let my steamers 'let loose'. Generally speaking, my top speed through turnouts is about 45SMPH, and that's on a rare occasion--I have one 'flat spot' on the layout and that's the yards at Deer Creek. So it's pretty much 'slow orders' when I'm operating, and so far, with few exceptions, my big steam has stayed on the track very nicely.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
richhotrain ATLANTIC CENTRAL: Again, I suggest that we roll a bare truck down our trackwork - if it stays on so should an unsprung lead or trailing truck. The one trouble with that test is that it does not account for a boiler and driver wheelsets that may not be in balance from front to rear. In my case, BLI long ago conceded that the boiler and driver wheel assembly was not balanced properly and that is why their solution is to add a stronger spring to the trailing truck to replace the weaker spring initially installed at the factory. They have reworked a large number of 2-10-2 and 2-10-4 steamers that have been returned to them for that reason. I would otherwise agree with you that rolling an unsprung bare truck down the track is likely to stay on the track. But that doesn't guarantee that the same truck will stay on the track when connected to a steam engine with balance problems. Rich
ATLANTIC CENTRAL: Again, I suggest that we roll a bare truck down our trackwork - if it stays on so should an unsprung lead or trailing truck.
Again, I suggest that we roll a bare truck down our trackwork - if it stays on so should an unsprung lead or trailing truck.
I would otherwise agree with you that rolling an unsprung bare truck down the track is likely to stay on the track. But that doesn't guarantee that the same truck will stay on the track when connected to a steam engine with balance problems.
Well in that case, that is simply a poorly designed model - good luck with anything that works to fix it.
Sheldon
ATLANTIC CENTRAL richhotrain: ATLANTIC CENTRAL: Again, I suggest that we roll a bare truck down our trackwork - if it stays on so should an unsprung lead or trailing truck. The one trouble with that test is that it does not account for a boiler and driver wheelsets that may not be in balance from front to rear. In my case, BLI long ago conceded that the boiler and driver wheel assembly was not balanced properly and that is why their solution is to add a stronger spring to the trailing truck to replace the weaker spring initially installed at the factory. They have reworked a large number of 2-10-2 and 2-10-4 steamers that have been returned to them for that reason. I would otherwise agree with you that rolling an unsprung bare truck down the track is likely to stay on the track. But that doesn't guarantee that the same truck will stay on the track when connected to a steam engine with balance problems. Rich Well in that case, that is simply a poorly designed model - good luck with anything that works to fix it. Sheldon
richhotrain: ATLANTIC CENTRAL: Again, I suggest that we roll a bare truck down our trackwork - if it stays on so should an unsprung lead or trailing truck. The one trouble with that test is that it does not account for a boiler and driver wheelsets that may not be in balance from front to rear. In my case, BLI long ago conceded that the boiler and driver wheel assembly was not balanced properly and that is why their solution is to add a stronger spring to the trailing truck to replace the weaker spring initially installed at the factory. They have reworked a large number of 2-10-2 and 2-10-4 steamers that have been returned to them for that reason. I would otherwise agree with you that rolling an unsprung bare truck down the track is likely to stay on the track. But that doesn't guarantee that the same truck will stay on the track when connected to a steam engine with balance problems. Rich
Hey, Sheldon, don't quit now. You have come up with a lot of good ideas and suggestions, not the least of which is rolling the bare unsprung truck down the track. Gotta try everything until I get these steamers performing flawlessly. Keep it coming.
Alton Junction
I have found this thread quite enlightening as it offered a lot of food for thought. I would enjoy seeing more opinions on the whole matter.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
OK Rich,
Here is a little more info about something I mentioned earlier in the thread.
I bought two PCM Reading T1's (4-8-4) when they first came out. I test rail them on the section of my layout that was operational at the time - 36" radius and larger (one curve is actually 54" R). They ran fine but I did notice they seems a little tail heavy and the offset drawbar was rubbing the tender frame. I filed the tender frame to correct the interference.
I lettered the first one for my ATLANTIC CENTRAL and took it to a friends layout during the weekly meeting of our Round Robin group. His layout has 28-30" radius, all impeccable hand layed track (he is an NMRA Master Modeler).
First, the smaller curves required we couple the tender in the rear position, but even with that we had a number of pilot truck derailments.
Afterwards I examined the loco to find it was indeed tail heavy and poorly balanced and that the smoke box was empty - apparently for a future smoke unit. I added several ounces of weight in the smoke box to balance the loco. And repeated this with the second one.
They now run fine at my house or his. So there are two lessons here. What works when you don't push a machine to its design limits may not work if you do approach the limits - AND - find and fix the real problems not the symptoms.
The pilot trucks were fine, but you can't expect them to track well if the whole loco is tracking poorly.
So that was a 4-8-4 with 70" drivers - 36" radius they ran fine even with "flaws", 30" radius was a problem.
So just think how much more you are pushing the engineering limits with a 2-10-4? I'm not saying it can't be made to work, but if the loco has the kind of inherent flaws as you discribed, similar to the T1 - tail heavy - that is the real problem.
Maybe BLI has or can fix that with a stiff trailing truck spring - most likely at the expense of pulling power - or maybe not. But a boiler that is "noising" and hunting will always be a problem on sharp curves.
ATLANTIC CENTRAL OK Rich, Here is a little more info about something I mentioned earlier in the thread. I bought two PCM Reading T1's (4-8-4) when they first came out. I test rail them on the section of my layout that was operational at the time - 36" radius and larger (one curve is actually 54" R). They ran fine but I did notice they seems a little tail heavy and the offset drawbar was rubbing the tender frame. I filed the tender frame to correct the interference. I lettered the first one for my ATLANTIC CENTRAL and took it to a friends layout during the weekly meeting of our Round Robin group. His layout has 28-30" radius, all impeccable hand layed track (he is an NMRA Master Modeler). First, the smaller curves required we couple the tender in the rear position, but even with that we had a number of pilot truck derailments. Afterwards I examined the loco to find it was indeed tail heavy and poorly balanced and that the smoke box was empty - apparently for a future smoke unit. I added several ounces of weight in the smoke box to balance the loco. And repeated this with the second one. They now run fine at my house or his. So there are two lessons here. What works when you don't push a machine to its design limits may not work if you do approach the limits - AND - find and fix the real problems not the symptoms. The pilot trucks were fine, but you can't expect them to track well if the whole loco is tracking poorly. So that was a 4-8-4 with 70" drivers - 36" radius they ran fine even with "flaws", 30" radius was a problem. So just think how much more you are pushing the engineering limits with a 2-10-4? I'm not saying it can't be made to work, but if the loco has the kind of inherent flaws as you discribed, similar to the T1 - tail heavy - that is the real problem. Maybe BLI has or can fix that with a stiff trailing truck spring - most likely at the expense of pulling power - or maybe not. But a boiler that is "noising" and hunting will always be a problem on sharp curves. Sheldon
Sheldon,
Thanks for this additional input. A very interesting discussion to say the least.
Sheldon has the right idea, you MUST tune your steam locos to get the best out of them. They are not, as the manufacturers try to convince us, plug and play models. They need work before they enter service on your model railroad just so that you can get the best performance out of them that's possible. Not one of my GER steam locos is as they came out of the box. Everyone of them was fine tuned and as a result of that and taking care to carefully hand-lay my track, derailments were unknown. Except for operator error or obstructions on the track. I could fearlessly back 16 car trains from one end of the layout to the other, at line speed, and not derail.
Check the centre of balance. Put the loco on a 12" ruler with the six inch mark centred on the drivers. Have a pencil or something else under the six inch mark as a pivot. Does the loco balance? No? Then fix it! Add weight to the light end so that the loco balances. Not perfectly as that's almost impossible but at least as close as you can get it.
Check the gauge on all wheels and fix the ones out of guage.
Remove the springs, they are not needed on well laid track and with a balanced loco. As I keep reminding people, for every action (The spring pushing down) there is an equal and opposite reaction (The spring also pushes upwards) and this lifts a very slight amount of weight from the (leading) drivers.
Finally. Do NOT operate large steam locomotives on toy train curves, those under 30 inch radius and expect them to run well. They won't, regardless of what the manufacturers tell you. On less than 30" curves about the largest steam engine you can run is a 2-8-2 and even then you may be pushing it. Besides, engines larger than 2-8-2s look really stupid on less than 30" curves. :-)
Best of luck.
Cheers
Roger T.
Home of the late Great Eastern Railway see: - http://www.greateasternrailway.com
For more photos of the late GER see: - http://s94.photobucket.com/albums/l99/rogertra/Great_Eastern/
rogertra Finally. Do NOT operate large steam locomotives on toy train curves, those under 30 inch radius and expect them to run well. They won't, regardless of what the manufacturers tell you. On less than 30" curves about the largest steam engine you can run is a 2-8-2 and even then you may be pushing it. Besides, engines larger than 2-8-2s look really stupid on less than 30" curves. :-)
I have just declared this as my rough rule of thumb. Multiply the number of driver wheels by 4.
The result is the minimum radius of curve that I must have to run a particular steam engine.
So, a 4-6-2 needs a minimum of 24" radius curves, a 4-8-2 or 4-8-4 needs a minimum of 32" radius curves, and a 2-10-2 or 2-10-4 needs a minimum of 40" inch radius curves. Since I have 32' radius ciurves on my double main line, I hereby ban all 2-10-2 and 2-10-4 steamers. Seriously.
richhotrain rogertra: Finally. Do NOT operate large steam locomotives on toy train curves, those under 30 inch radius and expect them to run well. They won't, regardless of what the manufacturers tell you. On less than 30" curves about the largest steam engine you can run is a 2-8-2 and even then you may be pushing it. Besides, engines larger than 2-8-2s look really stupid on less than 30" curves. :-) I have just declared this as my rough rule of thumb. Multiply the number of driver wheels by 4. The result is the minimum radius of curve that I must have to run a particular steam engine. So, a 4-6-2 needs a minimum of 24" radius curves, a 4-8-2 or 4-8-4 needs a minimum of 32" radius curves, and a 2-10-2 or 2-10-4 needs a minimum of 40" inch radius curves. Since I have 32' radius ciurves on my double main line, I hereby ban all 2-10-2 and 2-10-4 steamers. Seriously. Rich
rogertra: Finally. Do NOT operate large steam locomotives on toy train curves, those under 30 inch radius and expect them to run well. They won't, regardless of what the manufacturers tell you. On less than 30" curves about the largest steam engine you can run is a 2-8-2 and even then you may be pushing it. Besides, engines larger than 2-8-2s look really stupid on less than 30" curves. :-)
That's a pretty good rule, but it has one flaw, driver size. A Russian Decopod (2-10-0) has very small drivers and thereby a shorter wheel base (18' - 4"). A SP GS4 (4-8-4) has very large drivers and thereby a long wheel base (21'-6") even though it only has 4 drive axles.
The rule I use is based in prototype practice - actual scale feet - in my case no steam locos with a rigid wheelbase longer than 20 feet. I don't own either a Russan or a GS4, but the GS4 fails the wheelbase test. My Reading T1 (4-8-4) with their 70" drivers pass the test at 19"-3".
But there is no doubt, your rule will save you lots of aggravation as it is well within good engineering practice for these models.
A quick study of steam locos will show you that for the most part, east coast railroads prefered shorter rigid wheelbases, west coast railroads did not seem to mind long wheel bases. This is largely because the much of the trackage in the east has lots of moderate radius curves. They wanted locos that could go moderately fast all the time, everywhere. With people and towns close together high speeds where not really important.
In the west there are a few tight mountain crossings with tight curves, but those are overshadowed by MANY miles of flat, straight, open country with very broad curves. So it was more important to be able to haul big tonages at higher speeds (bigger drivers = higher speeds) even if you had to go much slower through those few tight spots.
The east coast exceptions to this were generally restricted to specific routes where they could be effectively used.
Just compare driver sizes of east coast Northerns to those used out west. Count railroads and loco ownership of 2-10-2's, and larger locos.
Compare a C&O 2-6-6-6 to a UP Big Boy - similar power on two completely different wheel base arragements. And yes the C&O was an east coat railroad that had a few monster wheel base locos, but they had better track than most. And even at that, there are reports of how hard many of those locos where on the trackage. They actaully evolved backwards from 2-10-4's to 2-8-4's and the 2-6-6-6. What does that say?
I have a continuing fascination with Dearborn Station here in Chicago and the Santa Fe operations as its primarly tenant. The ATSF had an engine servicing facility, complete with round house and turntable at 18th Street, a little over a mile from Dearborn Station.
However, the curves in the tracks leading into the engine servicing facility were sufficiently tight that most ATSF steamers were unable to use the facility.
I've been playing around with a couple of my larger steam engines , I did my track work and most of the scenery but used Diesel engines most of the time for testing, anyways having problems with front and rear pilot wheels climbing as they just seem light. I got some more research to do but other than fixing a couple track problems I now have some ideas to follow up on, good post.
Lynn
Present Layout progress
http://cs.trains.com/mrr/f/11/p/290127/3372174.aspx#3372174
Wow, a revival of a 10 year old thread - - AND IT IS MINE!
Man, does that bring back memories. The secret to keeping the pilot truck and the trailing truck on the rails is the spring. It has to be strong, and it has to be tight. It is difficult to add weight to those trucks without having the weighted truck hit the chassis. There is just no room to speak of.
This is actually a subject I have thought about lately.
All previous HO SGRR layouts only had two steam locomotives, an 0-8-0 and a 2-8-0. I never had this problem.
Now, for the final layout , I have accumulated a 2-6-2, two 4-6-2s, a 2-8-0, five 2-8-2s, two 4-8-2s, a 4-8-4, a 2-6-6-2, and a 2-8-8-4. Suddenly I have a lot of pilot and trailing trucks.
I hope they stay on the track!
-Kevin
Living the dream.
I have always found the trailing truck to be even more sensitive than the pilot truck.
For whatever the reason.
There are, in fact, multiple reasons, and solutions for them. But #>€* Kalmbach will not let me finish typing them.
For toy trailing trucks with a center pivot and bolster slot, reverse the bolster so it's down close to railhead level: this lets you fit the longest possible spring and gets the dynamics correct.
A proper trailing truck will have its forward pivot loose and 'sprung', with the downforce balanced by a spring arrangement near the rear. Ideally this would work like the prototype, at the outboard corners of the rear of both the locomotive and truck frame, but toy curves may make that extremely difficult; it is also fun to get the rear spring to allow the truck to pivot laterally without friction.
I'm going to pay attention to this thread as I am getting my first BLI steamer. A 2-8-0 in GN colors. Gonna try to keep that leading truck in check.
JJF
Prototypically modeling the Great Northern in Minnesota with just a hint of freelancing.
Yesterday is History.
Tomorrow is a Mystery.
But today is a Gift, that is why it is called the Present.
I find it interesting that in a previous post, someone stated that adding weight to the pilot or trailing trucks it would reduce the weight of the drivers to the rails. I do not think that is correct. A spring between the pilot and the loco could do that, but not weight.
woodoneI find it interesting that in a previous post, someone stated that adding weight to the pilot or trailing trucks it would reduce the weight of the drivers to the rails. I do not think that is correct. A spring between the pilot and the loco could do that, but not weight.
I agree with your analysis. Weight to the lead or trailing trucks is below the frame, so I think it would have no effect on the drivers themselves.
Excellent selection of postings on this subject,.
..that I am currently running some experiments on with several of my Bachmann 4-8-4 Northerns running thru Peco 3-way turnouts.
Brian
My Layout Plan
Interesting new Plan Consideration
railandsail Excellent selection of postings on this subject,. ..that I am currently running some experiments on with several of my Bachmann 4-8-4 Northerns running thru Peco 3-way turnouts.
I have an older Bachmann Northern (with the Bowser mechanism), and it is a bit finicky also, but not worse than my brass engines. I don't recall changing anything to it to go through tight curves and turnouts.
I also have a Bachmann 2-10-4, that was only happy with 30" curves. A real problem on my layout that has a few 22" curves. I ended up grinding down the flanges on the 3 middle drivers. It can now go through anything as long as I don't rush through. I should say that the front and rear wheels work fine through the curves and turnouts, when running at a reasonable speed. Like the real ones did....
Simon
Old PECO code 100 three way? They are pretty sharp from what I recall. There are no magic bullets that change the laws of physics.
I have found that each new steamer will find a flaw in my trackwork that always worked before. Steam engines always find them, usually at turnouts but not always. After fixing the trackwork my steam engines are fine, but there's always a few weeks where I have to go slow and watch the trains all the way around because an engine might derail at any time.
It takes an iron man to play with a toy iron horse.
Funny this came up, I was just working on keeping the leading trucks on the track, found out a little bend on the copper piece was all it took. I needed more pressure on the front of the trucks, the rear wheels follow no matter what
Hope this helps someone! I know there are lots of these old models out there, maybe not super popular but they can really pull and have real lasting power
Dave
Dave Banta
Modelling the Northern Pacific
I have an older Rivarossi Pacific that I love running. But I've had to tweak the pilot truck to keep it on the rails.
Obviously the first step is a thorough check, not only of wheel gauge but of cleanliness of the entire assembly, perhaps along with the tiniest oiling of the surfaces where its spring contacts the upper and lower surcfaces it bears on. If I oil it, though, although barely, it will always be a dirt magnet. The only way to avoid that is to never use oil or grease. I stopped oiling, and now lay down a thin graphite layer using Neolube, a graphite suspension that self levels as it dries. Neolube and products like it are excellent for many uses, but one should remember that the graphite layer they leave is mildly electrically conductive.
I checked that the upper and lower ends of the spring coil aren't dragging against the upper or lower bearing plates, because even the tiniest catch from such a small object could affect its travel. If I found a rough spot I'd address it with superfine sandpaper instead of a file; even the finest files leave marks.
If a truck's vertical spring or the surface it bears on has been painted, check that dried or uneven paint isn't a source of a hangup. Such lightweight moving components don't need much of a bump, to hang up on. Even a bump as a spring travels across its bearing surfaces could cause a problem.
We sometimes forget that the vertical spring in the truck does two things: 1) it puts downward force on the truck assembly; and 2) it puts upward force on the rest of the engine front. Item 1 can be desirable; item 2 not so much.
Best practice seems to be that balancing a moving vehicle's weight should be focused on the driving wheels. Upward force of a pilot truck spring may adversely affect that balance, especially if the truck spring is really 'vigorous,' and should be countered by rebalancing weight on the drivers if it can't be avoided altogether.
If the pilot truck won't stay on the rails doing anything with the spring is likely to induce an ongoing need to tweak something, rebalance the engine, tweak it as a consequence of the rebalancing, and rebalance it again. The problem may well be that the truck is just too light. They're really small, but the solution is to add weight to the truck, which doesn't affect anything else on the engine. Changing or adjusting the spring might not really or permanetly solve anything, and may induce other problems. Any suggestion by a manufacturer otherwise is just plain bad advice.
I avoid problems with the spring by adding weight, but only to the components of the truck in such a way that no further upward force is transmitted through the spring to the rest of the engine. On the Rivarossi Pacific the pilot truck's main component, other than the axles/wheels, is a flat plate that serves to hold everything together. I glued two bbs to the bottom of that plate, toward the outside and in between the two axle spacings. Painted, they're barely visible, and have done the trick.
From now on if I have a problem with a forward or trailing truck derailing I'll add weight to the truck, not to the locomotive. Heavier wheelsets in the truck could also do the trick.