Class 455/8 Modern Image EMU

[Arun Sharma]

A project that I've been working on for some time as a spare time indulgence rather than as a kit design to sell is the rather angular but stylish class 455/8 as currently operated by SWT on its Waterloo suburban/commuter routes.

The 455 class units are based on the BREL designed 20metre Mk3 bodyshells which were common to a whole host of pre-privatisation EMUs and DMUs. Inded, the first class 150 DMU was built by taking a 455 bodyshell and modifying it so that a diesel engine and suitable transmission could be fitted.
My basic design started life following a series of visits to photograph these units and then transposing the measurements into Autodesk Inventor with the following result [after 3D printing]:

The CAD design itself of the whole DTSO car is:

with separate doors and seats together with the various MU jumpers and underfloor bits to follow. The rear half of the car, when doubled, forms the entire TSO car which obviously save money and time. The power car of the 4-car set is almost the same as the TSO but has different bogies and a rather different air bag suspension mounting and some odd jumper connections on the rear end but nothing that can't be done in an hour or so when I get some time.

The 3D printed bodyshell had its first outing at the Guildford 7mm Trade show a couple of months ago in primer - which seemed appropriate as these cars are everyday stock on the Waterloo-Guildford routes:

 

[Arun Sharma]

Current work is centered around producing the BT3 bogies for these units. These aren't commercially available in the form used on these cars so again, a bit of 3D CAD is called for. The current design is:

this - the trailing bogie is similar but without the steps for the driver. I may need to do some work on the suspension balloon however. The final outer cosmetic bogie should be lost wax brass with an inner etched wheeled chassis. The power car aka MSO has a rather different bogie design - more akin to a HST bogie in general appearance but that's a way off yet.

 

[Arun Sharma]

This is what the inner chassis and bogie design looks like at the moment:


I'm going to have to find some way of adding something like a transverse bolster to the chassis pivot so that the whole thing can hang at the right distance below the solebar - a 3D printed transverse block connecting the two air suspension units is probably going to be the way to go.

 

[AdeMoore]

On my watch list! I see you name turn up on Tony Teague thread on RMWeb so aware of your line of work.
interested in seeing this 3D printing process though from CAD to print.

 

[Arun Sharma]

interested in seeing this 3D printing process though from CAD to print.

Thank you
I wrote three articles for the Scalefour Society journal [numbers 180-2 inclusive] that cover some of the philosophy and concepts of 3D design - Whilst in some respects these are a little dated now that is only in terms of their not being completely up to date rather than any redundancy. They are still worth digging out and reading if you know any S4 members.
3D printing is purely a means to an end - of itself it is no more useful than a word processor in the hands of someone who has some issues with literacy. Wheras in the hands of Wm Shakespear, Philip Pullman or JK Rowling [to mention a few] ....... many things are possible.
2D and 3D CAD design is really nothing more than an easily taught way of looking at the world as a collection of cubes, spheres, cylinders and cones. These can then be deconstructed as flat 2D shapes which are then pulled to an appropriate extruded length and combined with other similar primitive shapes.

 

[AdeMoore]

Thanks for the reply Arun, not sure I do know any S4 members but hey.
I can only marvel really at what you do!
I downloaded tinker cad once as I was told that’s a good start point!
Couldn’t get it or didn’t spend enough time trying to get it! Some plumed for Fusion 360 back then a step beyond my level of skill I thought.
watching with interest.