3F or 4F?

Discuss Bachmann Model Railway products and related model railway topics here.
muggins
Posts: 588
Joined: Sat Sep 24, 2016 11:24 am

3F or 4F?

Postby muggins » Wed Feb 05, 2020 3:05 pm

I'm beginning to feel the need of yet another 0-6-0 tender locomotive, and Bigmet's comments about the Bachmann 3F (below) have set me wondering about a Fowler. TBH I can't even remember what the difference is between the real 3F and 4F (apart from in my trainspotting days we saw mainly 4Fs), and I can justify either on the layout, but - which one do I go for if the numero uno priority is good low-speed performance on DC control? Are they to all intents and purposes the same mechanism?

Bigmet
Posts: 8237
Joined: Tue Aug 14, 2007 2:19 pm

Re: 3F or 4F?

Postby Bigmet » Wed Feb 05, 2020 3:46 pm

Other than the sample to sample variation that has to be expected in manufactured products, they are equivalent. Same motor, same design layout, just lightly adjusted for the dimensional differences.

In reality the 3F was enlarged to produce the 4F design, the final standard 0-6-0 for the MR and subsequently the LMS group; last in a series of 0-6-0 designs that started in 1850, and which were very influential on the UK railway.

muggins
Posts: 588
Joined: Sat Sep 24, 2016 11:24 am

Re: 3F or 4F?

Postby muggins » Wed Feb 05, 2020 5:44 pm

Much obliged, Bigmet. Thank you once again.

Bigmet
Posts: 8237
Joined: Tue Aug 14, 2007 2:19 pm

Re: 3F or 4F?

Postby Bigmet » Thu Feb 06, 2020 8:57 am

muggins wrote:...which one do I go for if the numero uno priority is good low-speed performance on DC control? ...

Bach's 0-6-0 mechanism is OK, and with good feedback control runs sweetly enough; since I use DCC a Lenz or Zimo decoder will be making the mechanism OBEY! such that you cannot tell what kind of motor, geartrain and flywheel arrangements it may have inside.

But my choice 0-6-0 tender loco purely on mechanism running quality grounds is Hornby's J15. Five pole skew wound motor, flywheels and a 44:1 reduction. That runs very smoothly on a basic DC resistance controller. (I believe their 700 to have much the same mechanism, and have not yet sampled their J36, but seen no complaints.) It doesn't hurt that the loco itself is small and pretty. Just in case that's of interest...

muggins
Posts: 588
Joined: Sat Sep 24, 2016 11:24 am

Re: 3F or 4F?

Postby muggins » Thu Feb 06, 2020 10:30 am

Bigmet wrote:... Just in case that's of interest...


I've actually got two of those :)

Ref DCC and slow running, when I returned to the fold after my 30-year hiatus, I knew nowt about DCC other than it cost, so I asked around (elsewhere) online before decided to stick with what I know. I'm still miffed that NOBODY even hinted at the one thing that would have sold me on it straight off despite the increased cost viz. slow running ...

Whatever, my understanding (a purely relative term) is that the 700 mech is a J15 minus one flywheel, and I haven't investigated the J36 on account of (a) it's too expensive for me and (b) it's too Scottish.
Last edited by muggins on Fri Feb 07, 2020 6:49 am, edited 1 time in total.

Richard Lee
Posts: 258
Joined: Tue May 08, 2012 6:00 am

Re: 3F or 4F?

Postby Richard Lee » Fri Feb 07, 2020 6:42 am

My Hornby 700 class runs very well, very quietly and smoothly. It is one of my 3 favourites of what I have now. I use DC, usually a Gaugemaster Combi with a HF1 "electronic track cleaner". I use it for goods, when running my layout in ST modes, whether western sector (former LSWR) or middle sector (former LBSCR) SR mode.

Bigmet
Posts: 8237
Joined: Tue Aug 14, 2007 2:19 pm

Re: 3F or 4F?

Postby Bigmet » Fri Feb 07, 2020 11:24 am

I have now taken the step required to correct the lack of the J36.

This one is no fit for my KX inner suburban modelling during BR's steam to diesel transition, however:
I like 0-6-0s. This was the loco that powered the UK's steam railway.
Most of them are very handsome, and all of them qualify for 'handsome is as handsome does'.
I don't at present have a single steam loco representing the Scottish steam engineering tradition.
Every 0-6-0 purchased will encourage the production of more, hopefully.

Where once it was necessary to build all the 0-6-0s a 4mm layout required, unless prepared to make do with 'Triang's doesn't look like a 3F at all' Midland 3F, the present state is a positive feast for those that like 0-6-0s. With a dozen classes either available or on the way as good RTR OO models we are on the way to decent national coverage.

Bigmet
Posts: 8237
Joined: Tue Aug 14, 2007 2:19 pm

Re: 3F or 4F?

Postby Bigmet » Fri Feb 07, 2020 12:39 pm

And no sooner ordered than arrived (18 hours from placing the order, despite going for the cheap 'whenever' shipping option.) Looks even better in the hand than the pictures, very good example of the small late nineteenth century general purpose 0-6-0, much like the C class and J15. Hornby have put a lot of metal in the loco, so it weighs a useful six ounces (185g) which will be more than adequate for traction, and it ran at a smooth and quiet dead slow straight out of the box. Instant favourite!

muggins
Posts: 588
Joined: Sat Sep 24, 2016 11:24 am

Re: 3F or 4F?

Postby muggins » Fri Feb 07, 2020 12:50 pm

Bigmet wrote:I have now taken the step required to correct the lack of the J36.


And I've just bought myself a new 3F as an alternative to the two C Class locos that I've had to return to MRD. The first one derailed coming off the turntable and thereafter flat-out refused to work for no obvious reason apart from a meter across a pair of wheels showing open circuit, and incredibly the replacement which arrived yesterday (and was an even better runner than the first one) failed due to a front connecting rod coming adrift at one end!

It's possible that my eyes deceived me even with the magnifying glass involved, but the crankpins on the C class seem to screw into the wheels rather than be pressed in, which is fair enough - until you consider that the head of the crankpin is a plain flat disc. If we could have found the blessed thing I'd be sure about that, but if it is indeed the case, that strikes me as a seriously bizarre design detail.

At least the crankpins on the 3F seem to be nice sensible hexagons.

ETA - And in case you're wondering how an LMS 3F is a substitute for a Southern C class, the answer is Rule One :)

Bigmet
Posts: 8237
Joined: Tue Aug 14, 2007 2:19 pm

Re: 3F or 4F?

Postby Bigmet » Fri Feb 07, 2020 2:16 pm

Bachmann and Hornby have used hex headed bolts for crankpins as standard on all the 'current standard' product that I have seen. (Given the supply disruptions reported from those involved in the business of getting our models manufactured in China, you will notice the caveat 'that I have seen'. I would not be surprised if some alternative parts were substituted on occasion.)

Over the past twenty years since Bachmann's very good WD 2-8-0 appeared, I have seen a couple of such crankpin bolts with too short a plain shank which promptly unscrewed, and that may have been the trouble with yours, or just not fully seated at assembly. Equitably distributed too, one on a Bach product, the other on a Hornby. I took substitutes off a Bachmann purchased cheap as a 'breaker', most likely they come from the same parts supplier.

muggins
Posts: 588
Joined: Sat Sep 24, 2016 11:24 am

Re: 3F or 4F?

Postby muggins » Fri Feb 07, 2020 3:19 pm

Bigmet wrote:... I have seen a couple of such crankpin bolts with too short a plain shank which promptly unscrewed, and that may have been the trouble with yours ...


OK, it's my eyes. Hex heads they are, and my money would be on too short a plain shank on this one. If it was simply insufficiently tightened on assembly, I doubt it would nhave stayed there for the best part of 40 minutes running at moderate speed. But who knows?

Whatever, praise be once again to Model Railways Direct for their excellent customer service.

Richard Lee
Posts: 258
Joined: Tue May 08, 2012 6:00 am

Re: 3F or 4F?

Postby Richard Lee » Fri Feb 14, 2020 10:33 am

The Bachmann 3F tender 0-6-0 that I ordered from Kernow is an attractive model, and runs very well. It made a bit of a racket when I started running it in (wheels pounding on un-ballasted second radius oval glued to a chipboard base), but it got quieter quickly. Once running in was complete, and I tried it out on the proper layout, it was quiet, and not bothered by the problem points to the BLT goods siding. (About 2/3 of my locomotive don't like these points in one direction along the curved path.) I can't speak about the 4F because LMS is a bit of a side interest for me, but if the OP is still considering a 3F, then I think that they would be pleased with it.

Edit: The running-in oval uses the cheap Bachmann train-set DC controller. My main layout uses a Gaugemaster Combi with an HF1 "Electronic Track Cleaner". No idea about DCCing because I have no medium-term intention to go for DCC.


Return to “Bachmann”

Who is online

Users browsing this forum: No registered users and 8 guests