Sooo, I needed a stable Loco Cradle in a hurry...
(I do hate when inspriation to Get-a-Job-Done strikes, but you can't lay hands on that tool you really need right this moment...
...fantastic way to waste valuable/rare time and effort, searching for the tool you need just to get-started...)

- couple of pieces of Foamcore, and an offcut of corner-packing foam
(a piece of lint-free offcut material, say the front of a discarded cotton T-shirt, could also work in a pinch)

- Carved and notched using the not-sharp end of an X-acto knife

 

- Folded up and hotglued together
(makes a useful little tray for all manner of things, and if enlarged, could form the basic for a "cassette" staging system... the fold-up bottom/sides make for an impressively rigid and flat "U channel" assembly!)

- Notched at each end, and foam packing hotglued in place 

- and ready for use...

 

Honestly, took longer for the Hotglue gun to warm up than it took to do everything else,
let-alone the time it's taken you to read this...

Now, where's the decoder I was going to put in that Shay?

Happy Modelling,
Aim to Improve,
Prof Klyzlr

PS for those wondering how the "sheet of cotton material" alternative would work,
- run a bead of hotglue along the "rear" long-wall
- press an edge of the cotton sheet into the hotglie bead
- once dry, drape the sheet forward so it's overhanging the "front" wall (closest to the user/camera),
so there is a shallow "U" shape in the cotton sheet
- run a bead of hotglue along the front wall and press the cotton sheet into it
- trim excess cotton sheet, and you're done...
...The cotton sheet forms a kind of "hammock" to support whatever shape the loco is...