Bachmann 46 to P4 using Ultrascale conversion

[John Donnelly]

Got my Ultrascale conversion for the Bachmann Class 46 yesterday and, after I'd figured out how to remove the bogie sides and bottom, the conversion took all of 30 seconds

However, I'm finding that the loco is incapable of negotiating a B6 turnout - the pony wheels are OK but, as soon as the first set of main wheels hit the curve, they derail. Although it is my first ever turnout, I'm happy that the track is to gauge as a Bachman Class 20 and parcels van (converted using Gibson wheels) can manage the turnout with no problems.

I've checked the back to back on the wheels and all is well. I appreciate that a B6 is, relatively speaking, a fairly sharp radius bit I wouldn't have expected the 46 to fall off...

Any ideas?

John

[waveydavey]

I'll be watching this thread closely. I don't have a 46 but I do have a Bachmann 40 which has essentially the same mechanism.

My 40 resisted all attempts to get it to run on my P4 track and it derailed at will anywhere on the layout. Having tried a few ideas, such as allowing the inner axle on each bogie a bit more room to move up and down and adding weight to the pony axle, which failed I came to the conclusion that the 1B1-1B1 chassis is 'a bad design' and my plans to have a 40 on Longcarse West were shelved.

I hear the new Bach 40 will have a better mechanism so my next layout might get a 40 but this, sadly, doesn't help with your issues.

Mike Anson has managed to get Bachmann Peaks to run on Western Road so it might be worth tracking him down and asking for a few hints.

Cheers

David

[John Donnelly]

Cheers David

As it turns out I'm waiting on an order for a set of wheels for the Class 40 as well... Both it and the 46 are too big for the micro layout I'm currently building so there's plenty time to get it sorted before the 'big' layout takes shape...

John

[the fatadder]

Very strange,

I have an Ultrascale fitted peak, and my old layout had some pretty lousy track work. Yet the peak was one of the more reliable runners (it could also handle the mk1 DRAG test track at high speed and that had some truly awful trackwork!)

However Bachmanns quality control in the chassis department can be pretty poor, I'd recommend checking that all the wheels are level (and also that the keeper plate is fully in position)

[John Donnelly]

However Bachmanns quality control in the chassis department can be pretty poor, I'd recommend checking that all the wheels are level (and also that the keeper plate is fully in position)

Thanks for that, I'll check.

John

[Horsetan]

Now's the time to "encourage" Ian Penberth and Justin Newitt to consider all-sprung bogie etches for the 40 and 44/45/46......

[jim s-w]

Hi John

(just a note for all those new to p4 who might be slightly perturbed by the suggestion that peaks and 40s might need sprung bogies - they don't!)

Anyway - does it behave exactly the same both ways round and does it derail in both directions? Have you checked the back to backs? (normally ultra scales are ok but it's a good habit to always check)

When you say it derails as it hits the curve does it take the curved road ok at the tip of the point blades an derail later or is it off as it hits the point blades? Is it actually riding along the top of the rail before it derails? What happens if you take the inne axles out?

Cheers

Jim

[John Donnelly]

Thanks Jim,

Running some tests now, I've removed the 2 sets of pony wheels for now as they derail as soon as the hit the point blades.

90% of the time the leading bogie makes it through but the other 10% of the time, the leading wheels come off as soon as they hit the point blades. Even when the leading bogie makes it, the leading wheels of the trailing bogie derail as soon halfway along the curved rail...

Back to backs are fine - it turns out that the gauge through the point blades is a little tight but a very lightweight bogie parcel wagon makes it through so I figured that the 46 wouldn't have a problem given its weight...

John

[Terry Bendall]

I have not done a Class 46, or Class 40 for that matter, but have had occasional problems with Class 37s. One thing to do is to check the gauge through the turnout using the Roger Sanders/MINT gauge, as sold by the stores. This gauge is really invaluable for checking the parts that other gauges don't reach. Since you say the gauge is a bit tight in places, this might well be the cause, and I don't think the weight of the loco would make much difference then. However one trick I use is to put some lead weights on top of the chassis and run the loco through. That is a way of chercking if weight makes any difference. Hold the weights in place with Blu-Tac or similar. Running the loco without the body on is also a way of seeing what is going on. Your van going through might be because the wheels on that are a bit under gauge.

In addition to checking the back to back of the wheels, check also that they are concentric and are running on the axles without wobble. This should not happen with Ultrascale wheels but it is worth checking. In addition the leading bogie might need some springing on the top to help it stay on. By the way, also check that your back to back gauge is correct. A few years ago the Society did find a few around that were not accurate and of course check the back to back distance at the outside of the wheels not at the centre.

It isworth while having a detailed check of the turnout. Just because the Class 20 goes through, it does not mean that everything is correct. (In any case Bo-Bo locos generally behave better anyway) The bogie wheels derailing on the turnout blades suggests that the blade ends are not quite correct. Is it a hand built turnout or one from a kit? Has it been assembled correctly? Are the blades sitting down correctly. Is the stretcher bar correct? Is there any solder or paint in places where it should not be? Are the ends of the blades filed thin enough? Are the tops of the rails flat and level? Any humps in the rail? (Check these last two with a steel rule laid in edge along the top of the rail)

Lots of things to check, and in good scientific practice, only change one thing at a time.

Terry Bendall

[Horsetan]

....for all those new to p4 who might be slightly perturbed by the suggestion that peaks and 40s might need sprung bogies - they don't!)....

Why not

[Terry Bendall]

Why not

Perhaps because they can be made to work without springing.

Terry Bendall

[jim s-w]

Hi Ivan

They can be but it's important that people understand they don't need to be. Unless your track is really bad no diesels need to be sprung.

Cheers

Jim

[Penrhos1920]

Unless your track is really bad no diesels need to be sprung.

Cheers

Jim

WRONG. Having seen several diesels fall off straight flat C&L flexi-track I disagree. I've not got a 40 or 46 so I can't comment on them. But of those ex-RTR diesels I have got and friends have I can tell you that about a quarter or maybe more NEED springing, major surgery or ingenious tricks just to stay on straight flat track. It's called poor design and build QC by certain RTR manufacturers.

[John Donnelly]

Thanks for the all the suggestions, I think I've found the problem.

The inside wheels of each bogie are 'sprung' and it appears that there is not enough weight to depress the springs fully. As a result, the centre wheels of the CO-CO bogies are not sitting completely flat on the track so, when they hit the turnout, as they are not on the rail surface, they are coming off so I need to sort out the springing.

My newly converted 08 takes the turnout with no problems

John

[jim s-w]

Unless your track is really bad no diesels need to be sprung.

Cheers

Jim

WRONG. Having seen several diesels fall off straight flat C&L flexi-track I disagree. I've not got a 40 or 46 so I can't comment on them. But of those ex-RTR diesels I have got and friends have I can tell you that about a quarter or maybe more NEED springing, major surgery or ingenious tricks just to stay on straight flat track. It's called poor design and build QC by certain RTR manufacturers.

I am sorry but your comment is hugely unhelpful. There are loads of diesel layouts out there that have worked perfectly fine without springing and have done for years.

I have been operating P4 deisels for over 20 years, A quarter need springing is complete gibberish based on my actual experience! The only thing I can assume from your comments is that your track building is really awful (or you ar using the now infamous old stocks of gauge changing c&l track)*. However if you would like to name some classes and makes that have given you grief I will happily take some video (assuming I have the same) to prove they will work.

Cheers

Jim

*not to be confused with more recent c&l track

[ClikC]

Unless your track is really bad no diesels need to be sprung.

Cheers

Jim

WRONG. Having seen several diesels fall off straight flat C&L flexi-track I disagree. I've not got a 40 or 46 so I can't comment on them. But of those ex-RTR diesels I have got and friends have I can tell you that about a quarter or maybe more NEED springing, major surgery or ingenious tricks just to stay on straight flat track. It's called poor design and build QC by certain RTR manufacturers.

At the risk of elivating this to a arguement (Not my intension, as I'm acturally a huge advocate of springing for reasons other than just track holding. Bringing models closer to the prototype, smoothness of running etc, the list could go on). But You might be approaching the issue from the wrong end. I'm sure I read a discussion a while back about guage tightening with C&L flexi, but in the most part the track needs some quite severe roll (in terms of one rail being higher than the other) over a fairly short distance to make a Bo-Bo Deisel and/or Electric locomotive fall off the track. Co-Co and above I might be able to see your point, as the fixed all wheel drive axels can have a tendancey to rock on the middle axel. But I've never had to resort to 'Major Surgery' to get the very worst of them to behave, A Bit of opening out here, or a bit of filling there hardly consitiutes major in my book.

My experinces of Bachmann 40's and 45's is sharded with Rich (the fatadder), the 1-Bo-1 system having a rather crude from of semi-suspension acturally converts very well. With one of my 45's running almost perfectly on Matford (during happy hour) at the Exe MRS 2010 show with just a set of ultrascale drop-in's. IIRC the biggest issue was electrical pickups and the pony wheels derailing on a crossover which i think was suspected as being "tight to guage", but could well have just been my Back-to-Back being out.

I agree with Jim, in that no Deisel or Electric needs to be sprung, but probably completely disagree on the grounds that they should be sprung.

John, one issue I've encountered with the bachman Bo-1 drive system on one bogie of a Class 37 before I even converted it, was the plunger type springing used on the un-driven axel was binding at the top of it's throw. This was causing derailments on my Club's then perminant 00 guage layout. Since conversion and a little filing and wet and dry, it's never been an issue.

Regards

Matt

[jim s-w]

Hi matt

If someone wants to spring a diesel I have no problem with that and sprung stuff does look to ride better than unsprung. It's the claim that it's needed that I object too.

Cheers

Jim

[grovenor-2685]

But Jim, you put in your objection when no-one had claimed that springing is 'needed'. Hence provoking all this argument about nothing. The fact is that some diesels do not just work with a drop in wheelset but can need quite a lot of investigation and fettling, and some can be close to impossible. In all of this non-argument the idea of helping the OP has been lost, luckily he has now worked it out for himself.
Bo-Bo diesels are usually trouble free, Co-Co diesels designed as A1A-A1A similarly. Co-Co diesels with B1-1B set ups are suspect, Co-Co versions designed as C-C very variable, some are good others can be so banana shaped as to be essentially impossible to tweak enough. The same generally goes for the various versions of Peaks and 40s, you can be lucky or unlucky.
Springing is not 'needed' and no-one has claimed that it is, but equally just dropping in new wheelsets does not always work either. Over simplification does not help newcomers any more than overcomplication.
Regards
Keith

[jim s-w]

Springing is not 'needed' and no-one has claimed that it is,
Keith

Um, I said that to which one reply was "WRONG" so exactly how did you work that out? I never said straight drop ins work in all cases either so I dont believe I over simplified anything. In the case of the peak I have several and all work - I didnt use ultrascales but aside from that I didn't modify the chassis other than to add a bit of lead to the pony trucks

Jim

[jim s-w]

Hi John

Can you confirm that your peak works as a bo-bo? (just the driven axles?). Its worth adding a bit of lead to the pony truck if you want to (doesn't hurt)

Cheers

Jim

[jjnewitt]

Jim is right to say that springing is not needed, to say that it is would be wrong, plenty of locos have been converted to P4 without suspension and work fine. It would also be wrong to say that all RTR diesels can be converted to P4 simply by dropping in Ultrascale type conversion wheelsets and anyone who's had experience of an all wheel drive Co bogie willl no doubt second this. There are simple methods of making them works like Jim's method of using a slightly smaller diameter wheel on the centre axle. The only thing that should be done as far as diesels is concerned is model them in P4 , everything else is the informed (hopefully) choice of the modeller.

Anyway back to the heart of the thread. If the springing arrangement on the Peak is the same as on the original class 37 then the it is also the same as used on the cente axle on the 08 (bear with me). I had problems when converting the 08 as the centre axle wouldn't stay in contact with the track properly. I ended up putting a washer on the pin that locates the coil spring to lengthen the arrangement and it works fine now. It sounds as if you may have the same sort of issue John, though if it is the centre axle that isn't in contact with the rail then the spring arrangement on the rear axle may need shortening rather than lengthening. The spring shouldn't be fully compressed though. It should be able to move slightly up and down. Another point that no one has mentioned is the question of sideplay over the "driving" axles. That bogie has a very long wheelbase at 8'0" + 8'0" and if there isn't sufficient sideplay on one of the axles then that could explain why it's having problems with tight curves. A pic of the troublesome bogies in question might be helpful

[Terry Bendall]

Like Jim S-W, I have also converted lots of diesels to P4 without springing. To date the list includes: Bachmann 08, 20, 37 (both the earlier type with the four wheel drive and the later all wheel drive) and 66, Hornby 31, 50, 58 and 60, Heljan 33 and 47, and in most cases at least three or four of each and by now about fifteen - twenty 37s and 47s. Perhaps I have been lucky but they have all worked successfully except for a few of the early four wheel drive Bachmann 37s which needed tweaking and the Hornby 50s which also needed some work. I have not had any problems with bent or twisted chassis so again perhaps I have been lucky. The only ones that have Ultrascale wheels are the 08s - most of the rest use Black Beetle wheels, except for the Horby 31s, 50s and 60s which use Gibson conversion packs.

Like everything else, my view is that its your train set and if you want to spring the wheels then fine and doing so may well help with track holding. Another reason to use springing is that the loco then behaves like the prototype and you can see the wheels going up and down as the loco moves along the track. Of course the aim is generally to lay flat trackwork so if this is achieved you won't see any movement! . As I indicated earlier in this thread, there are lots of reasons why things fall off - the problem is finding what is the cause.

[quote="grovenor-2685"]Springing is not 'needed' and no-one has claimed that it is, but equally just dropping in new wheelsets does not always work either.]

Probably the correct statement is that drop-in wheels nearly always work.

Terry Bendall

[grovenor-2685]

Terry,
I don't see 40, 44, 45, 46 featuring on your list, but if you did not have problems with Bachmann 47s you were indeed lucky!

There are at least two versions of the Bachmann peak shassis, maybe more. The earlier ones were 1-B-1 bogies with pivotting pony trucks both ends. The springing on the pony trucks being critical and difficult to adjust, very likely almost eliminating the spring and weighting them as Jim mentioned may be the best bet, its certainly difficult to get just enough spring to keep the Ponies on track without lifting the drivers. Even when you have managed this and it runs OK light engine there are problems with the lateral stability of the short wheelbase (8ft) bogies with the buffers and couplings on a long overhang where a heavy load on the drawbar can twist the bogies. It is best to fix the inner Pony so it can't swing which largely alleviates this problem. The later version has the inner axle sprung but not pivotted and hence is a bit easier to deal with, refer http://www.norgrove.me.uk/classes24-25-44.htm

[Russ Elliott]

Am I right in thinking that the principle of the original Bachmann 1-B-1 sprung bogie is like this?

1-B-1-bogie.png

If so, the position of the point at which the body impinges onto the bogie is important, and will determine the track-holding of the axles. I think I would be inclined to sort the rear axle spring strength first, i.e. get the bogies running reliably without their front carrying ponies, and only then put enough strength on the pony spring sufficient for its track holding.

Justin's point about ensuring sufficient sideplay is also very pertinent.

[grovenor-2685]

Yes, the pivot and support point is in the centre of the B bit (ie not where it is on the prototype). One of the problems is excess side play.
Of course you need enough, but that is not a lot, similar to a pannier or a jinty.
Regards
Keith