Didn't they indeed!Ahh well let's see how far I get.
Do you have any recommendations for getting bogies and or bogie sides which would look prototypical, so far mark 1 and the like aren't ideal.
Off the top of my head, I can't think of anything that really looks like BR sprinter bogie. It also depends were you're going dimension-wise - the model is 12mm/ft (3xOO) or 1/25.4 which in my view is about right for rubber-sclae stuff to mix with LGB/Playmobil/Piko/USoutline etc. You can argue for anything between about 11.5mm/ft and 12mm/ft.
Is that just giving you your cross-section or length as well - ie are you building the vehicle more-or-less full length or shortening it? The mock-up is obviously short, but could well be half a vehicle, so I don't want to guess.
If you were running 10mm/ft, then the real thing is 2600mm wheelbase, round number metric (approximate) equivalent to 8'6", so the 84mm wheelbase USAt trains block is as close as gets ready-to-run. Wheels are a bit small, that's fixable for a price, but there are no sideframes that look even close to right, so you're going to be scratchbuilding those.
In 12mm/ft, that 2600 scales out as about 102mm. Nothing is bang-on, but the Piko Taurus/Br218 size block is close at 98mm. None of the Piko sideframes is really a good match for the 153, but the one of the taurus isn't too far off at a pinch I suppose. Here's a photo of the real thing :
To my mind it's still not that close, and obviously a loco sideframe, but that's personal choice. If that's no good, then you're into scratchbuilding.
The reason why I asked about vehicle length is that if you're doing a 12mm/foot cross section but shortened vehicle (the real thing is 22640mm over the cab faces, which would be just over 890mm in 12mm/ft), then there's some argument for following LGB's patented rubber ruler method - reduce the length to approx 75-85% of what you'd expect from the cross-section by losing a window/grill here and there and shortening all the others. Assume the passenger/drivers don't need much leg-room and fit bogies that are shorter than scale, but fitted with something closer to 'scale' size wheels. If you chop the thing down to the size of Piko's TEE coaches - 670mm - then it's basically 3/4 length. In than case I might be inclined to go with something like the HLW 3-inch block, though you'd still be up for scratchbuilding some sideframes. The 'standard' LGB diesel B-B block has similar dimensions, but it's generally more expensive, and I can't think of it having any suitable sideframes, so my choice would be the HLW.
No actual answer to the question asked, but I hope some of that is helpful.
Jonathan
g-bits.co.uk