HK Custom Shells

Found these today on Thingiverse, quite nice, representing Hong Kong;

Yellow Head

and

MLR

Both look great and are designed to go onto standard PlaRail suburban type chassis...

very nice.  The only problem with printing the shells from your personal 3D printer is that the shell is too stiff too bend to secure the body onto the chassis.

That's ok, nobody has ever said you have to use them, you can always go to Shapewise and pay £100 for a shell instead

It's actually Shapeways

Yea Shapeways is expensive but they are pretty good.

so I uploaded 3 MLR files to shape way for a test, it will cost $224.31 just to print them.  They cannot be built using versatile filaments.  I guess the shells cannot be bend to fit into the chassis.  only fine plastic material can be used to build the shells.

[Super]

Hmmm...the cost of ten new trains.....................

I also uploaded the yellow version as well.  it costs roughly the same and they can't use versatile filaments either.

This is what I was getting at, you can always use online print services, but they are not at all cheap and the results are often no better than can be achieved on home printers.  The issue of shells being inflexible is a trade-off between flexibility and durability.  PLA (the normal material) can be printed thinner and thus more flexible, but the downside is that it is then considerably weaker and can be prone to cracking or breaking, especially around the tabs used to secure the shell to the doner chassis.

Nylon would be a better material, but is very tricky to print with.  Similarly ABS may be better as it can be a little more flexible, but tends to suffer from warping and delamination especially unless you have a printer with a fully enclosed casing which are far more expensive and less common.  PETG may be an alternative, but one of the downsides of this material in this scenario is the colours it comes in, it is generally not easy to find 'solid' colours, most offerings are translucent so would require full priming and painting.  Again PETG can also be a little more difficult to use, although not as bad as ABS, Nylon or other exotic materials.

I think overall a better long term strategy will be to design not only the body shell but also a custom chassis as well, that way a better fitting mechanism can be designed, for example a screw on shell rather than a clip arrangement or similar.  But that level of commitment takes a lot more time which at the moment I simply don't have.  Maybe something for when I retire in a few years time

another solution is to print 2 dummy front end cars.  technically you use the Mr. Motorman car from the middle to power the train.  It will work.  I will have to think about it.