Buddy L?

[trammayo]

I own two of these "interesting" locos. I seem to remember someone posting a solution to the leading truck's penchant for leaving the track! I made some mods - removing the spring and the swivel plate and adding weight - but they were only effective 85% of the time. I run it (or would if it was 100%) on my trailer layout which has R1 reverse curves.

Before I make a new truck with a Bachmann 25mm wheelset, I just wondered if anybody had a link to the solution? Thanking you all in anticipation

 

[Tim Brien]

Ensure pilot and pony wheels are 'in gauge'. I purchased around ten of these and the Heritage Express variants. I found that all axles (including drivers) were well undergauge. Correcting the gauge did improve performance, particularly through points (switches). Ideally, the trucks need a longer pivot arm.

 

[trammayo]

Hi Tim - the B to B is less than 38mm - plus the parallel tread hardly helps centering.
Are they easy to re-gauge? I did try to move or twist the wheels but they were hard and fast.

 

[trammayo]

Hi Ross. Thanks for the link (which I've bookmarked). I cured my Bachmann stuff the same way and it works well - 99.999% of the time! The B*uddy * is a different kettle of fish as I've already got rid of the friction from the springs and swivel guide plate by removing same and then added weight.

I'm not one for chopping things up but did think of making a new truck with 25mm (nominal) wheelset with coned tread so it would centre again. The problem arises when it come round the curve and onto a straight which, co-incidentally, is a R/H point. Everywhere else it just crabs along until the next curve!

 

[Rhinochugger]

The other trick is to make a new pony truck bar, extend it so that the pivot point is between the front two driving axles. This means that the wheels are much more in line with the rails on a curve, rather than being in purgatory.

 

[trammayo]

The other trick is to make a new pony truck bar, extend it so that the pivot point is between the front two driving axles. This means that the wheels are much more in line with the rails on a curve, rather than being in purgatory.

I think that is what was done in the posting I'd like to look at. It may have been on GSM? I just didn't want to chop things up if there was a better way. Mind you, the copper coloured boiler will definately go if I mod the truck

 

[Tim Brien]

Mick,
the narrower the gauge the more the tendency for the pilot wheels to 'crab' down the rails (the trailing pony wheelsets when in reverse direction). This causes the wheelset to ride up the rail and derail. The pilot/pony wheelsets are in three pieces (the driving wheels are similar), two similar 'half' axles with square ends and a mating brittle plastic connector, much like the Bachmann wheelsets. The trick is to coax the wheelset half axle out of the centre plastic connector and superglue within gauge (1.575", around 40mm). Unfortunately, it is easy to get superglue on the brass wheel bearings, so tread lightly.

I found that the loco derailed through every set of points. I dismantled the loco and glued the flanged drive wheels ingauge, also inserting thin slices of brass tubing over the axles, either side to limit axle sideplay. This proved very effective as no loco derailed through switchwork after modification.

These locomotives were basically built to circle a Christmas tree only and are really little better than the other cheap toys one finds in a supermarket. Unfortunately, the advertising hype elevated their status and they were actually originally targeted at the LGB start set market. Advertising executives obviously had a very low opinion of model railroaders.

 

[ntpntpntp]

Yes, I agree the pony wheelsets on mine were too narrow and needed to be eased out a little so that they track through LGB R3 points correctly. Also not helped by the very basic "square" flange profile on the pony wheels on my Heritage Express example.

Not noticed any problems with the b2b of the driving wheels themselves, and thankfully these seem to have a better flange profile.

Cheap and cheerful, the whole set cost me less than £60. The wagons are perfectly usable and better wheels than some of the Bachmann stock I've had.

 

[trammayo]

I think, Nick, that I paid too much for mine. The second one was a bargain from a forum member!

I note what you say Tim - I'll try and pull the wheels slightly apart. If all else fails I'll revert to plan B and make a new bogie with a Backmann wheelset. I have a number of options now open to me (and all as cheap as chips). So if I cure it, I'll post a pic or two!

Many thanks everybody

 

[bobg]

As hinted at earlier there is a required length for the pony truck pivots (to axle). If that is incorrect then the truck will please itself how it tracks and most likely de-rail on occassion espescially on reverse curves.

There are two formula for calculating it, Von Borries formula and Baldry's. Having messed with this myself I can say that it makes little difference who's you use, the result usually comes out very nearly the same. It's based around the distance between the fixed (driving) axles centres, and over-all wheel-base. It ensures that the pony-truck axle stays reasonably close to 'straight across the track' in bends, i.e. radial to the centre of the curve.

Without looking it up I can't quote it here, but I soon found it with Google when I did it. I don't know the Buddy L but would suspect that the truck is too short. The B2B is also important as always; parrallel treads less so.

 

[trammayo]

Hi Bob - yes you're right about the truck pivot point. I took the simple expedient of turning the loco on its back and then trying to overlay a pair of R1 curves. With its present geometry, it is a rather uncomfortable marriage! I'll make a new truck and save the old one in case I'm daft to repeat my current problems. I don't like the flat treads which, together with B2B, exacerbate the problem.

 

[bobg]

Mick, whilst the flat treads are not true to 'life', they dont (in our scale) have a great deal of effect. The pivot point also isn't completely crutial but it does need to be within bounds. I would suggest to the nearest mm. is near enough (maybe 2mm). I went through this with my current 7 1/4" freelance and was amazed at the correct position, one came out so close to the rear driving axle centre that I still had to compromise. I mocked it up and it proved to be so close as to be impressive for accuracy. I eventually relieved (thinned) the axle to get it as close as possible to true. It isn't totally exact, but after preliminary testing I don't expect any problems, especially as it's trailing.

 

[trammayo]

Here's a pic - you can see the problem!

These were taken before I did my iniitial mods - the trucks were even more restricted then.

 

[bobg]

At a rough guess Mick the front pivot needs to be about 25-30 mm further back, and the rear on even longer, no wonder it doesn't track well. The wheels must be so out of line on the curve that they jamb in the check-rails on points.
I think I set up a spread sheet to try out different scenarios (mine's freelance). I'll see if I can find it. The measurements required are the over-all wheel base, the over-all driving axle wheel-base and the distance from the front truck axle to the first driving axle. Whole millimeters will be near enough.

 

[trammayo]

Whole millimeters will be near enough.

Cheers Bob. With my eyesight, that will be near enough!

 

[bobg]

Sorry can't find the spread sheet, I only seem to have kept the results, and the formula.

Pony truck centres

Von Borries formulae: R = D2 ? B2
2D

Where R is the required radius, D is the total wheelbase of the loco and B is its rigid wheelbase.

Baldry formulae: R = 0.5 (E- F2 )
( E ) (can?t find how to make a bracket bridge 2 lines!)

Where E is the distance from the pony truck axle to the centre of the rigid wheelbase and F is half the rigid wheelbase.

 

[Rhinochugger]

The other trick is to make a new pony truck bar, extend it so that the pivot point is between the front two driving axles. This means that the wheels are much more in line with the rails on a curve, rather than being in purgatory.

I think that is what was done in the posting I'd like to look at. It may have been on GSM? I just didn't want to chop things up if there was a better way. Mind you, the copper coloured boiler will definately go if I mod the truck

T'was probably me - I own a copper boilered one, that is now running on an Aristo 8-coupled brick

 

[trammayo]

Thanks Bob - I've saved it (and printed it out!) - it won't be this week or next but I WILL sort it

 

[trammayo]

The other trick is to make a new pony truck bar, extend it so that the pivot point is between the front two driving axles. This means that the wheels are much more in line with the rails on a curve, rather than being in purgatory.

I think that is what was done in the posting I'd like to look at. It may have been on GSM? I just didn't want to chop things up if there was a better way. Mind you, the copper coloured boiler will definately go if I mod the truck

T'was probably me - I own a copper boilered one, that is now running on an Aristo 8-coupled brick

And I have to ask the usual question (seriously though) - will it go round R1s comfortably?

 

[trammayo]

Having had two or three days to ruminate, I thought I'd take another look at the loco and utilise some of the advice offered on this thread.

Following Bob's postings, I worked out that the pivot point for the leading (and trailing) trucks should be around 122mm (nominal - there was a digital fraction!). So it cut a full size cardboard template for 120mm (centre of axle to pivot) because the were two convenient retaning screws in the base plate to secure the new trucks to (if I go down that road in the end).

So I temporarily disconnected the existing truck and slotted in template. I then overlaid an R1 curve to see the result (Pic 1). The line across the card represents the axle.

Not over happy about the results so put the truck back on and repeated the process (Pic 2).

I then followed up about the B to B and prised the stub axle off, inserted two 4mm I.D. brass washers as spacers and glued the assembly together (as suggested) with superglue (Pic 3). Sorry about pic quality - tried 5 times to get it right:thumbdown:

Then when the glue had dried I tested it out on the garden line. Mind you, there were never any problems on this line before so the true test will be on the trailer layout today.