Beyond the Kato 11-109 - the 11-108!

Back in February I completed number 6, a Simplex from FK3D styled on the Abbey Light Railway's 'Druid'. This ran on a Kato 11-109 as intended by the maker, although I had revealed a little more of it by removing the false 'skirt' under the underframe to make the end result more realistic. However, I always thought that it looked a little too 'perched' on the chassis, in particular too much clearance under the re-railing bars was a bit off-putting.

The inspiration for what follows was actually my yet to be built FK3D Lister locomotive, which takes advantage of a feature of the new-generation Kato chassis being built around a 'core' of weights holding the motor, flywheel, drivetrain etc to the point that the upper cover really only stops things falling out of place. I had also discovered the version of the Kato chassis (11-108) that had very little detail and was in fact noticeably narrower than the fake locomotive sideframes of the 11-109. My initial thoughts to somehow use a chassis without a cover and wondering how to fix it in place, turned to using a further-reduced 11-108 to lose 1mm in ride height.

The starting point, number 6 on a 11-109, with a frame height of 14.5mm and the 11-109 sideframes filling the space underneath.

The alterations required the the 11-108 chassis (stock Kato image used). The aim was the leave a raised area in the centre to match the opening in the body of the 3D print. In particular I will draw your attention to the cut at the right hand end of the top - do not cut to the right of the raised area as this will remove the clip that stops the motor moving backwards, I started this but soon realised my error! Cut along the opening about 1.5mm in from the edge instead and then file down the area to the right. All cuts were made with the top cover removed from the motorising unit.

The resultant conversion is seen with the original 11-109, we can see how much narrower it is and how the end platforms are lower than the 11-109 frame. The areas over the axleboxes were at about the same height as the 11-109 frame but I have chamfered them away to fit into the cut-away area under the body. I have painted the axleboxes matt black to better hide them and switched the baseplates over to give the new chassis the sprayed matt black one from the original chassis. 

In order to secure the new chassis in place I have used two screws which pass through the endplates into holes drilled in the underside of the body, centre at the rear and to one side at the front. As the motor protrudes out of the top of the cut-down chassis I had to remove an area under the bonnet of the print and reposition the weight that counterbalances the whitemetal driver figure. This view shows the slightly angled areas that will form the main interface between the new chassis and the body, inboard of the strips that sat on the 11-109.

The end result is a 13.5mm measurement to the top of the frame, bringing the rerailing bars closer to the rails and looking a lot less perched with the bonus of fresh air between the axleboxes and the ends of the loco.

So, was it worth it? I think so! Now you might be wondering why I didn't just cut away the old frame and carry out the same modifications, well I find the Kato plastic a little awkward to work and the less I had to remove the better, especially along the length. I also have memories of taking too much away from a 11-103 in the past and actually rendering it useless... but at least I have a spare motor for my older locos...

Colin