outside frames in 009

Since the early days of 009, outside frames have posed problems for the modeller. To this day, most 009 model locomotives seen on layouts are based on proprietary inside frame chassis, the owners having developed selective blindness to the situation.

So, many narrow gauge locos do indeed have inside frames.... the Talyllyn locos, the 4-6-0 ex WD Baldwin and Hunslet and the Fairlies and England engines of the Festiniog. After that, one gets pressed to think of other examples except industrial engines. The fact is that a huge number of NG locos had outside frames.

I cannot understand why a modeller would go to great lengths to detail a loco body and line it and then just stick it on a Minitrix chassis.

Some kits are now produced with outside frames. The best known are those produced by Backwoods. The chassis are very hard to build and even harder to repair. One chassis is an exception and that is the one used for the Darjeeling C class. This however relies on a tender motor with universal jointed shaft and traction is next to useless.  If the chassis would be used under a tank engine body with motor over the wheels, the situation would be far better.

a Lynton and Barnstaple Manning Wardle chassis by Backwoods

The C class Darj chassis. Fit a motor on the chassis under a tank engine and this will work!

push on cranks

Victors made an HO Sandy River. The chassis is superb, easy to build and has given excellent service on County Gate. Sadly, they have not yet got around to supplying just the chassis. Victors have ceased trading. Hopefully the kit will become available again but so far nothing. The chassis is an easy build although noisy in operation continues to slog on faultlessly.

Meridian a  Baldwin gas mechanical. This is an excellent kit. It can be difficult to order from this outfit, however.


RTR outside frame chassis


The first suitable outside frames loco for 009 was the dreaded Roco. One has to buy the entire loco which will knock you back nearly 100. The cylinders and valve gear are well modelled. However....... after a short period of service, the chassis self destruct and the Mashima motor develops such a rough spot that the loco will almost throw itself onto its side. A wonderful chassis for about 12 hours running!

a cut down Roco chassis

The useful part is the valve gear and cylinders. These can be ordered separately Roco dealers. The parts list can be found on this link (page1) and this link for page 2. Part number 116295. This is the fastest way to get valve gear! This is for a single cross head slide. Alternatively, one can order the valve gear for the HOe Roco Mikado. PDF file can be found here. The cylinder valve gear set is No. 122875.

Fortunately, other manufacturers have come to the rescue.

N Drive Productions


This is a new range made in Scotland and will include 4 and 6 coupled outside frame chassis. They are excellent in design and drive on all wheels, thus reducing strain on rods. One has to be patient with Neville as he is a one man band! When more readily available, these chassis will make the basis of many wonderful locos. The wheels are very small rather sadly. The chassis shown below has a wheelbase about half way between 'Russell' and the L&B Manning Wardles. As yet, their outside frame chassis is not fully developed and is not yet available.

There is still no sign that this chassis will reach availability and delivery problems still seem to be the order of the day.

N Drive six coupled chassis


Grafar class 08


This is an excellent chassis and easy to modify. It is a tad wide, however for some prototypes. The price is not bad too at about 50. For those who model the Lynton and Barnstaple and prefer a different chassis to the Backwoods kit, the wheelbase is almost correct and the Backwoods chassis can be easily modified to drop on to it. This is a project we have successfully undertaken. After some running, I do have to say however, that the plated wheels of this chassis are prone to slipping on grades.

I have experienced several loose wheels. This is what I suggest:

On initial stripdown, degrease axles and wheels and run into the wheel boss, a small quantity of Locktight 603 and leave overnight. This should prevent these stupidities.

Several phosphor bronze are often on in contact with the wheels....check for this..

Positioning of the Roco cylinders. Remove motor. Use 5 minute epoxy to attach and have the return crank already fitted into the rear crank. There is then a short window of opportunity to ensure that there is free movement of the gear.

Once the cylinders are fastened, push the chassis along to check for any binding between the coupling rod and the slide bar support bracket. Only then replace the motor but glue this in position as well, as the extra weight of the valve gear can cause the motor to 'jump' and strip the gears.

The chassis has undergone several modifications on later offerings and just gets better and better.

I have even managed to modify it to be eight coupled.


kits for the Grafar chassis

TP Models

The first kit produced for mounting on this chassis was by Bernard Taylor of TP Models. It is a 'what could have been' model of a narrow gauge Armstrong Whitworth diesel electric loco. The quality of etching is superb and two of these kits were the basis of our articulated River Avill.

unfinished prototype - photo Mick Thornton

TP models


This is the second kit supplier who produced a decent kit to go with this chassis. The valve gear is etched.  Hopefully, the valve gear etching will also eventually be available independently. While Victors is no more, one hopes that kits will be re-introduced. The etched valve gear for this engine is superb but sadly this kit is no longer available.

RT Models

RT Models produce a white metal kit for a Harrogate Gas Works Drewry 6w diesel (works no.2262 of 1949). It looks tidy enough. The cab is cut down as was normal for this line.

The superb RT Peckett

Robert also produces frets for valve gear and even has a casting available for the keeper plate.


Backwoods kit with Grafar chassis

Backwoods chassis with a Grafar hiding inside! see how here. The motor must be moved into the cab area. click on image to enlarge

 two rebuilt chassis for our Mallet 'River Brue' see here

Lilliput diesel locomotive

Another newcomer is an H0e model of an outside frame diesel.  It is offered for sale at a little under 70. Reports are that it is a superb runner.



Without a doubt the best chassis of the possibilities comes from this very expensive but excellent manufacturer.

At around $244 USD, the Bemo HOe Diesel Loco Class VL3 looks extremely overpriced until you look at the quality of engineering. Every wheel is driven by decent gears and the whole thing is just 'right'. I have seen two Leek and Manifold tank engines based on these chassis and extremely desirable they are too.

The Bemo chassis installed into a Backwoods kit. This loco is 'Exe' on our Bratton Fleming layout and runs perfectly.

Parkside Dundas


A new contender is a chassis supplied by Parkside Dundas for the Penrhyn  main line locos. This is a wonderful new development. Supply is again very limited and several months waiting list is the order of the day.

photo by Mick Thornton



A most exciting development has been announced from Minitrains. Outside frames which can no doubt be modified including the crank shapes. It is due for release spring 2014. The valve gear leaves much to be desired as it stands.



Another exciting development is the announcement that this company is to offer replicas of the L&B Manning Wardle. Preproduction photos show an excellent model with slightly simplified Joy gear. A must for all L&B fans I should say when it finally surfaces.

back to basics

Narrow gauge locos with outside frames are a bit like sausage dogs and it is almost impossible to see their wheels. For the most part then, I worry little about spokes and such like.

extension kits

From time to time these have been made available but seem scarce these days. They are quite easy to make yourself however. Firstly, discs of thin brass or nickel silver have to be made.

Once you have your discs, solder your axle extensions into the disc. Make sure that the joint is very well made. I use a jig to make sure that the axles are accurately fitted.

Now trim of the axles to the length required leaving the rear flush with the disc. Now the cranks can be fabricated quite easily using 1.5mm thick brass. Solder stock together and file the block to the shape required.

The cranks must then be accurately drilled on a good drill stand to give a good fit for the axles and crank pins. I favour using 14 BA screws for the pins and tap the holes and screw them in. They are then soldered and the head sanded off.

The discs with their axle extensions must now be fitted to the wheel sets. Here, a jig has to be turned to make sure that they are accurately aligned. This is a tool which will continue to serve as long as you use the same wheels for other projects.

It is now time to fit the cranks. Remember, cranks are always fitted at 90 degrees to each other.  You can buy proper quartering tools and frankly I think they are worthwhile. If you have one, attach the cranks using Loctite 603. This glue will give you time to fiddle around until the quartering is perfect. Once satisfied, leave for 24 hours to set.

If you do not have a quartering tool you must fit the wheel sets to your chassis. Attach the cranks using Loctite 603 and add the coupling rods temporarily. You have to time to fiddle around with the quartering until the wheels and rods turn with no tight spots. It is a good idea to have the coupling rods drilled for a clearance fit to the 14BA pins. The holes can be opened out later. Leave untouched for 24 hours.

Make sure that the cranks are all equally spaced from the discs.

The outside frames can be then added as they are slotted. They can be made of Plasticard or metal.

You now have an outside from loco. The first one I made this way was my K1 Garratt in 1972 and it is running well to this day!


extended axle wheelsets

It is sometimes possible to have wheel sets provided with extended axles. This is the case, for instance, with the Bullant chassis. Such sets are also available from Romfords. If you are modifying a commercial chassis, this option is not usually available to you. This method is better of course, if you can do it.

push on cranks

You can buy push on cranks from Victors Scale Models and Meridian (Meridian use this method for their Baldwin gas mechanical). These are very good provided that your axles or axle extensions are of the correct diameter. They can be firmly attached with Loctite 603.

A Victors chassis with push on cranks