Too spring or not to spring, that is the question?

 
  hosk1956 Deputy Commissioner

Location: no where near gunzels
Doing some load tests for timetabling on a friends railway recently, his Eureka R was was having trouble traversing his spiral with the assigned load (which I thought was quite moderate), further investigation showed the grade within the spiral actually increased for a short pinch which was affecting the R's performance.On closer inspection at eye level as the train passed I reckon I could see the rear off the engine dip down at that point and all the weight was coming off the front drivers, and losing traction on the front drivers, we put a lump of lead over the front of the engine as a test but it made NO difference, the same problem occurred.
My theory is that the springing is too light which let the rear of the engine dip down like that under load.
My solution which I may try on my engine is too remove the springing and make it a more rigid wheelbase, has anybody experienced a similar issue and what are peoples thoughts.
And yes I know all the usual guff about prototype loads and removing carriages, fixing the track yada yada yada, let's not go down that path and stick to the question at hand please.

Wayne

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  The railway dog Train Controller

Location: Adelaide Hills
Real steam locomotives tend to dig down at the back under heavy load so I suppose electric mice would too. Is there a way of stiffening up the rear springing alone?
Though you'd think that your placing a weight on the front would've tended to keep the drivers on the track.
  M636C Minister for Railways

While I don't have one myself, there have been comments about the trailing truck on the R class being less than flexible.

It is possible that the track depression is transferring the locomotive weight to the unpowered trailing truck from the driving wheels.

If it is possible to remove the trailing truck and test the locomotive again on the particular section, this might help determine the problem.

The additional weight on the front would rule out a similar problem with the leading truck.

M636C
  richter170 Junior Train Controller

Hi all,

This has been raised before. While the pony truck can be tight, try loosening it first by a qtr of a turn on the screw.

Look closely at how it operates. I have modified a few R class and they have no pulling issues at all with 6 cars up grades.

The main issue is the footplate doesn't lift up far enough when the loco is under load and the track is slightly rough, the engine will catch the tender and lift up at the front.

The main thing is weight. They need some put in. One piece over the front pony truck, in the sand dome up top, and mould pieces around the boiler there is 1mm clear to get it in. Between the grate and the side of the loco near the cab put one piece each side.

I also put some right up to the front under the smoke box. Some people may not want it there as you can't see through the frame.

Al.
  a6et Minister for Railways

Doing some load tests for timetabling on a friends railway recently, his Eureka R was was having trouble traversing his spiral with the assigned load (which I thought was quite moderate), further investigation showed the grade within the spiral actually increased for a short pinch which was affecting the R's performance.On closer inspection at eye level as the train passed I reckon I could see the rear off the engine dip down at that point and all the weight was coming off the front drivers, and losing traction on the front drivers, we put a lump of lead over the front of the engine as a test but it made NO difference, the same problem occurred.
My theory is that the springing is too light which let the rear of the engine dip down like that under load.
My solution which I may try on my engine is too remove the springing and make it a more rigid wheelbase, has anybody experienced a similar issue and what are peoples thoughts.
And yes I know all the usual guff about prototype loads and removing carriages, fixing the track yada yada yada, let's not go down that path and stick to the question at hand please.

Wayne
hosk1956

While I do not have an R class & model NSW I remove the spring from the leading bogie on all my engines, & simply add a couple of strips of lead flashing on the top side of the bogie, secured with some roof & gutter sealant, which allows removal if needed.  The springs are generally too strong even cut in half, & tend to push the front down, meaning the rear driving wheel can often be not making any contact with the track, thus only 2 sets of drivers are doing the work.

I would start there, & then if no better remove the spring from the rear bogie. I think in the previous Eureka thread that dealt with the R class & this very issue, someone improved their model with some adjustment to how the rear bogie is attached to the underneath of the model. It seemed as if the way it is connected is too rigid & causes the rear part of the engine especially the rear set of drivers to not make proper contact to the rail.  

The suggested fix was actually in the last couple of pages of that thread.
  Roachie Chief Commissioner

Location: Kadina SA (formerly NSW)
While I do not have an R class & model NSW I remove the spring from the leading bogie on all my engines, & simply add a couple of strips of lead flashing on the top side of the bogie, secured with some roof & gutter sealant, which allows removal if needed. The springs are generally too strong even cut in half, & tend to push the front down, meaning the rear driving wheel can often be not making any contact with the track, thus only 2 sets of drivers are doing the work.

I would start there, & then if no better remove the spring from the rear bogie. I think in the previous Eureka thread that dealt with the R class & this very issue, someone improved their model with some adjustment to how the rear bogie is attached to the underneath of the model. It seemed as if the way it is connected is too rigid & causes the rear part of the engine especially the rear set of drivers to not make proper contact to the rail.

The suggested fix was actually in the last couple of pages of that thread.
a6et

I think the OP is talking about the idea of removing the 6 springs from the main drive axles, so that the coupled wheels don't have any movement....(at least that's the way I read it).

I'd be a bit scared of doing that....you'd have to add packing to the top side of the journal to replace the "air gap" that now exists where the springs used to "live".

I agree that the 4 things to address are:

1) Front bogie spring....reduce/remove spring and add some lead weight
2) Rear bogie.....make sure it can ride okay without lifting the rear drivers. This may require "surgery".
3) Fall plate....make sure it can move enough so that it doesn't affect the loco-to-tender relationship. It needs to be able to swing freely.
4) Add as much extra weight to the boiler/firebox/cab/chassis as possible

Roachie
  a6et Minister for Railways

I think the OP is talking about the idea of removing the 6 springs from the main drive axles, so that the coupled wheels don't have any movement....(at least that's the way I read it).

I'd be a bit scared of doing that....you'd have to add packing to the top side of the journal to replace the "air gap" that now exists where the springs used to "live".

I agree that the 4 things to address are:

1) Front bogie spring....reduce/remove spring and add some lead weight
2) Rear bogie.....make sure it can ride okay without lifting the rear drivers. This may require "surgery".
3) Fall plate....make sure it can move enough so that it doesn't affect the loco-to-tender relationship. It needs to be able to swing freely.
4) Add as much extra weight to the boiler/firebox/cab/chassis as possible

Roachie
Roachie

Bill, you're right re the OP, did not pick that up, I guess I overlooked that part as I don't recollect that any other models have "Wworking?" springs over the main wheels, so is it really a first?  As I have not found that on any of my models.

Certainly the adding of weight is needed & as suggested there is room inside the boiler & especially the dome which gives good location over the leading & middle drivers, if room was found at the edge of the leading end of the firebox, that would help. On my Austrains 36cl, I found space behind the main reservoir air tanks under the running boards to silicon in some lead flashing, which is not seen in operation, that allows a good amount of extra weight to be added.
  hosk1956 Deputy Commissioner

Location: no where near gunzels
I think the OP is talking about the idea of removing the 6 springs from the main drive axles, so that the coupled wheels don't have any movement....(at least that's the way I read it).

I'd be a bit scared of doing that....you'd have to add packing to the top side of the journal to replace the "air gap" that now exists where the springs used to "live".

I agree that the 4 things to address are:

1) Front bogie spring....reduce/remove spring and add some lead weight
2) Rear bogie.....make sure it can ride okay without lifting the rear drivers. This may require "surgery".
3) Fall plate....make sure it can move enough so that it doesn't affect the loco-to-tender relationship. It needs to be able to swing freely.
4) Add as much extra weight to the boiler/firebox/cab/chassis as possible

Roachie
Roachie

Correct Roachie,

That was my thought, I have other engines with no springing (or springs that are that hard they might as well not be there) with no operating problems.

To address your points:-

1) Haven't looked at the front bogie spring on either mine or the mates, so will do.
2) Rear bogie has been adjusted and isn't the problem.
3) The fall plate on both mine and the mates snapped off while endeavouring to insert that damn plug, which by the way will never ever ever ever be removed, what a cow of a thing. So no footplate to create an issue.
4) When I noticed the front drivers lifting we hung a very substantial lead weight over the front of the engine, it came to a wheel slipping halt at exactly the same place! with the front drivers still lifting from the rail head.

The track does dip up a little in the area thus increasing the grade, I thought it might be creating a hump past that point that was letting the front drivers lift but it doesn't appear so.
Before I return to the railway I will make a couple of test platforms that I can use to check the hump and dip in this area, I have made a couple that is used on the club garden railway, they being a couple of flat platforms with a pair of bogies under each, you just push them around and not the ride height differences between the two platforms, the platforms should obviously be the same height, if you put a substantial overhang on them you can see variations very easily, on well laid track there should be very little variation.

So plenty of testing to do, I was feeling the water to see if others have been experiencing problems and what their solution may have been, removing the springs will be a last resort, thanks for your responces, feel free to keep the conversation going.

Wayne
  Roachie Chief Commissioner

Location: Kadina SA (formerly NSW)
Wayne,

Next thing I'd try is to remove both front and rear loco bogies and try it as an 0-6-0. Also, while the bogies are off, place the loco on a piece of glass (eg: glass-top table, mirror or even a large-enough photograph in a frame etc) and try to ascertain if all the drivers are touching. See if a cigarette paper will slide under any of the 6 wheels (if you can find someone who still rolls-his-own).

Roachie
  LaidlayM Chief Commissioner

Location: Research
Personally I don't believe that the number of driven wheels touching the rail makes any difference on a model.  I compared many reviews of US prototype models and drawbar pull was the same for either the 4 axle or 6 axle version of a particular loco.  It's simply weight on driven wheels.

Mark
  NSWGR1855 Deputy Commissioner

Personally I don't believe that the number of driven wheels touching the rail makes any difference on a model. I compared many reviews of US prototype models and drawbar pull was the same for either the 4 axle or 6 axle version of a particular loco. It's simply weight on driven wheels.

Mark
LaidlayM

Mark,
you are correct about drawbar pull and number of wheels touching the rails. One thing that has not been mentioned is are the carriages free rolling or are they to heavy? If the wagons do not roll down a 1 in 50 grade, then it is not the locomotive that is the problem. If the carriages are heavier than the AMRA standard, then you are asking allot of your locomotive.

Terry Flynn.
  Aaron The Ghost of George Stephenson

Location: University of Adelaide SA
Mark and Terry have it right, for a given locomotive mass, the number of rail contacts makes no difference to load pulling ability. This is a widely misunderstood concept within the hobby.
  pazz Beginner

Not being smart here, but is this a loco problem?. Could it be more of a track issue. Can the transition between the two grades at the 'pinch' be adjusted, if it's constructed with the all thread method, or is the spiral fixed.

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