DCC Fitting Series: Bachmann Class 03

The development of my new layout, Woodford Wells, has been an interesting one. Not least for delving into and learning the brave new world of DCC. (Not really new for most of you, but new for some of us!).

So far the DCC construction and design process has been fairly smooth. The track was easy to wire, the control system simple to learn and the point motors (iP Cobalts) work perfectly. I knew that the hardest part of the DCC learning curve would be upgrading my existing rolling stock. I’ve had to open up a couple of locos in the past to upgrade lighting or to trouble shoot faulty motors and it’s never been an easy process. The fear of damaging delicate and expensive scale parts is always prevalent even with older models. This is something to consider when ‘chipping’ stock yourself. Secondly there was also the assumption from myself that once a chip was inside a loco, the performance would dramatically increase…

This series of fitting guides hopes to shed light on how easy it is to fit chips to given locos (starting with the first 5 that have already undergone the upgrade process) and to investigate what the performance is like after the conversion.

Class 03 by Bachmann

For all of these guides so far I’ve had help from Bromsgrove Models, a site with a comprehensive list of DCC fitting guides. I’d recommend studying these before you consider self-chipping any of your own stock.


Bachmann Class 03 in BR Blue (Weathered).

How Easy Is It To Fit?

Very. And that’s why I’m starting with this model.

Simply take out the NEM pocket adapters (a small flat head screwdriver will help). This reveals two screws.


Remove the two screws circled.

Remove these screws, and bingo, the body lifts off with ease.

It’s then a matter of fitting the chip. For those not in the know (as I wasn’t but a few months ago) DCC chips comes in a variety of sizes, the most common are 8 or 21. But for some of the smaller locos, like the Class 03, something a little smaller is required: A 6 pin chip. The number of pins a chip has, and do correct me if I’m wrong, directly corresponds with how many functions the decoder can store. A function is a programmable ‘extra feature’ a loco may have beyond it’s motor drive (i.e. directional lighting, cab lighting, sound etc). The more pins you have, the more functions the chips seem to accommodate. Most of the time locos only come with the need for 1 additional function – lights. This is just as well as the chip I’ve bought – the Bachmann E-Z Command 36-558A – can only accommodate 1 additional function, but that’s all I need at this stage.


Pin 1 is identified by a small white square.

Make sure you fit the chip the right way round. Pin 1 (above) must align with socket 1 which is at the right-hand edge of the strip (bellow). All chips should tell you which pin is pin 1.


Pin 1 on right-hand side. Click to enlarge.

Refit the body and NEM pockets and you’re good to go.

Fitting Score: 9/10. Dead easy, just make sure you fit the chip the right way. Not as obvious as a 21 pin decoder, but it’s hard to get wrong.

How Does It Run?

On Analogue the Class 03 was one of the best (if not THE best) performers I had. The gearing is set up in such a way that you can crawl along the track on DC accurate to real life. It was like moving on silk it was that smooth of a mechanism. The Class 03 was high on my list of locos to get chipped when I started the new layout and I instantly had high hopes in terms of making that silky smooth performance even better.

I was quite disappointed.

The ultra-low speed operation is now jerky and uneven. It smooths off a bit when you get to the locos lower-mid range (perhaps a scale speed of 6-8 mph), but even at this pace it’s not quite as good as it once was on DC.

This is when I discover, with a little research, that there are differing premiums of chip. I wrongly assumed a chip would be a chip – how much can one manufacturer differ from another?! – and that a Bachmann at least one would work perfectly in a Bachmann model. Forum trawling highlights that many folk struggle to find a kind word to write about Bachmann’s 6-pin chip, and sometimes struggle to find anything nice to say about Bachmann chips full stop. I certainly have come to learn quickly from the fitting of the other 4 locos I’ll eventually do guides for, that the results of Bachmann chips differ wildly. But then this could boil down to the age old “you get what you pay for.” I’ve seen recommendations for Lenz and Zen chips, but as you’d expect some of these come at twice the price of the evidently budget Bachmann one.


Bachmann 36-558A E-Z Command Chip.

DCC Chip/Running Score: 4/10. I say all this without actually trying an alternative chip – I’ll try another decoder and report back, but until then, the Bachmann chip + 03 combo really doesn’t cut the mustard. Don’t get me wrong, it works (and the cab light looks rather smashing all lit up) but I was expecting more. It also causes a problem with push-shunting coaches with sprung loaded NEM coupling arms – I use delayed action Kadee couplers and the jerky behaviour sometimes frustratingly re-couples the knuckles.


Lights On!

Overall Score: 6.5/10. Bachmann are all over the place here. They’ve created a model that’s easy to DCC fit, and for that – for DCC newbies like me – I thank them profusely. However, the chip as far as I can tell is dreadful and doesn’t do a superb model and mechanism justice.

I hope you’ve found this guide useful, please check back soon for more loco fitting advice, oh and if anyone has any other suggestions/alternative chips for the Class 03 – please comment bellow!

Other Locos In the DCC Fitting Series:

  • Class 17 (Coming Soon)
  • Class 25
  • Class 47 (Coming Soon)
  • Class 128 (Coming Soon)

– Andy Carter

Model Railway Track: Code 75 or 100?

So you’ve picked a scale to model in. It would be reasonable to think that the most important part of railway modelling – i.e. the track and the stock – would be an accurate scaled down version of the real thing. Well you’d be wrong.

Image from modelrailforum.com

OO Gauge suffers from a historical anomaly that means it’s rolling stock is actually too big for the track in runs on. In the early 20th century British model manufacturers had decided to compete with their American counterparts who had just launched O gauge. (Half of O Gauge, 3.5mm to the foot scale or 1:87). However to keep costs down they were still manufacturing models with wind up mechanisms. This method of propulsion was proving hard to fit into 1:87 scale models. The solution was to enlarge the models to 1:76 scale (or 4mm to the foot). Instead of enlarging the track with it – a costly exercise, the British manufacturers simply continued to import the American HO track and built the models’ axle width to cope accordingly. At the time, when manufacturing techniques were cruder than they are today, this inaccuracy was not so noticeable. Unfortunately the mismatch in scale sizes stuck, and is still in use by all the major companies (Hornby, Bachmann, Dapol, Heljan etc) today. The inaccuracy may still be hard to spot with the majority of models, but put a British OO Gauge model next to an American or European HO counterpart on the same track and the difference will certainly be noticeable.

So what can be done?

Some modellers do what the British manufacturers never did and properly enlarge the HO track to it’s true 1:76 scale. This is known as EM Gauge (and an even more accurate scale is P4), although you might often hear it referred to as ‘Fine Scale.’ This is a rather drastic step and almost exclusively requires scratch built track to be constructed by the modeller in question. It also requires all the wheel bases and axle widths to be altered on the models themselves to cope with the enlarged track. The results are certainly remarkable, but this is usually beyond the Novice modeller such as myself.

Track Codes: What’s the difference?

An alternative is to look at improving the rail dimensions without altering the actual gauge. You may have heard people talking about Track Codes – these are alternative varieties of off-the-shelf HO/OO Track with different rail heights. The gauge is exactly the same, but the rail height varies in an attempt to be more accurate. The track you get in any Hornby, Bachmann or Peco starter set is almost definitely Code 100 (sometimes referred to as ‘Set Track’). The ‘100’ simply means that the rail is 0.1 inches high. If this were to be scaled up along side OO Gauge rolling stock, the rail height would be almost 30% higher than it’s real life equivalent. Code 75 track (with a rail height of 0.075 inches) is far more accurate. If you scaled this up it would this time be 3% lower than it’s real life equivalent. It’s still not perfect, but it’s much closer to the mark than Set Track.

Codes 100 and 75 are the most common but there are of course other varieties: Code 83 is used to improve the accuracy of North-American-Image rail heights and Code 60 can be used on UK-Image layouts to mimic 3rd and 4th rail systems.

Do you need to worry about the difference?

Absolutely not. Many great show grade models have used Code 100 track. When ballasted properly you can still achieve a great effect, and it certainly looked good on Langstead Junction… However, Code 75 track will look that tiny bit better still. To help you make up your own mind I’ve got hold of some Code 75 track to do a comparison.

In the following picture the shallower rail height is certainly noticeable on the Code 75 track. The sleepers also look less chunky, and better spaced.

Top: Code 100 Bottom: Code 75

The rail height is really noticeable side on:


Left: Code 100 // Right: Code 75

With stock added, the Code 100 doesn’t look too bad and from this angle the difference is less noticeable:

Left: Code 100 // Right: Code 75

Left: Code 100 // Right: Code 75

The front on comparison isn’t great due to the light, but it’s just about clear that Code 100 looks a touch big from this angle although there’s not much in it.


Left: Code 100 // Right: Code 75

From above the Code 100 sleepers look too chunky, and the rails are noticeably bigger. From this angle Code 75 looks great:

Left: Code 100 // Right: Code 75

Left: Code 100 // Right: Code 75

From some angles Code 75 looks noticeably better, but form others the difference is hard to tell. On the other hand Code 100 is tougher, cheaper and curved radius’s come in pre-formed pieces (or set track to you and me), whereas Code 75 is only available in long strips of Flexi-track and can therefore be more challenging to create authentic looking curved sections.

As with most things in modelling there are pros and cons to each side of the argument. I’ve decided to use Code 75 from Peco for my new project, Woodford Wells, as the majority of the track is fairly straight and easy to shape.

If you want to read more about Track Codes I strongly recommend visiting Model Rail Workshop to read the full study and comparison. This post certainly helped me!

– Andy Carter

How To Improve Old Rolling Stock: Lighting Experiments

Recently I undertook a little project to breathe new life into some old Hornby coaching stock. This was mainly focused on painting and coupling but I did briefly mention the possibility of adding lighting to bring a whole new dimension to a model with out-of-date tooling.

Lima Class 121

Those of you who follow me on Twitter may have seen my continued effort to freshen up my old stock in my undertaking of recommissioning a Lima Class 121:

Continue reading

How To Improve Old Rolling Stock: Introduction

As you may well know, I originally got this hobby in my teens, being forced to take a break when I ran out of space and went to uni.

Spin forward 10 years and I now have a large quantity of rolling stock that I inherited from the offset, some of which is really starting to look quite dated and tired held up against modern offerings. The quality of models has improved leaps and bounds in that 10 year absence from the hobby, so this poses a question: How can I bring those old clapped out ‘toy’ coaches in line with the brand spanking new super detailed models on offer today?


I’m going to take you through a few processes I have been trying out to breath new life into my old stock, in particular this rake of Hornby LMS (Railroad) Coaches.

Beware: I’ve waffled a fair bit whilst writing up this project, it’s quite long! To break it down and to make it easier to digest I’ve broken the process down into three steps:

Part 1: Painting
Part 2: Coupling
Part 3: Gangway Connectors
Prologue: Cost

Let’s Begin: Part 1 >>