Thursday 22 December 2022

Underground Skips

Being a hard working ordinary gravel line Nystrup Gravel's primary type of rolling stock is of course the side-tipping skip. From an old list we know that the company owned a mixed range of standard steel skips of German-inspired DIN-type as well as a few British Hudson-skips. Recent research in the company archives has now revealed that the company also had a number of Hudson underground skips with U-tubs and narrow profile. 

Workshop manager Petersen inspecting a newly arrived 3D printed underground skip. 

With documentation for underground skips on the prototype Nystrup Gravel my model of the gravel line obviously had to have some as well. I found some rather credible looking 3D printed U-tub skips resembling a well known British type built (or at least marketed) by Hudson. Recently I have had rather positive experiences with 3D printed products including loco parts, porcelain isolators and figures. My first 3D model was a Schöma locomotive back in 2013 when I was modelling in 1/35 scale.

Four standard skips set aside for the weekend. On my 1/19 scale model of the Nystrup Gravel I have a mix of DIN- and Hudson-type skips just as the real gravel company had. A single Hudson can be seen far left. Now a new type of skip will soon join them.

Nystrup Gravel wasn't home to any underground activity (except for some resistance activities against the German occupation 1940-1945) and the reason for having underground skips were most likely some limited clearances inside one of the buildings in the Nystrup Gravel complex. The few images I have so far seen of the wagons shows them dumping ash and general waste in the emptied part of a gravel pit. Observations that could point to their use for transporting waste from within the production facilities.

A page from a Hudson catalogue showing various U-shape skips for underground use. Here sourced from the website of The Yorkshire Group of 16mm N.G. Modellers Ltd.

The 3D printed kits are sold as 'SM32 16mm Scale Hudson Skip Kit' on ebay. It is mentioned that the parts are printed in polyethylene terephthalate glycol. The kit consists of two large parts (frame and tub) as well as four smaller parts (wheels). I had 6 skips shipped as I like to have a number of the same type of wagon. On Danish industrial railways a single wagon of a type wasn't the norm, as most industries bought rolling stock in batches. I continue that shopping habit.

One of the U-tub skips taken directly from its zip-lock bag. More awaits unpacking in the background.

Newly unpacked skip seen from a slightly different angle.

Skip and tub separated with wheels in the foreground.

Close-up of the 15 mm diamater wheels which are of questionable quality, at first glance at least.

The parts are rather finely printed with no large marks from the printing proces. On some surfaces there is a very fine layering pattern visible. The bottom of the U-tub isn't genuinely half-round but 'stepped'. Both effects are known disadvantages from the printing proces and the design/drawing phase. The layering effects have diminished in the recent years due to advances in printing technology, but ruined most small scale 3D printed models some years back. Usually the effects are less serious in large scales where it is also a little easier to remove or cover them with surface texture and paint.

A view of the underside of the skip frame.

As customary on late Hudson products the open end of the U-profile is on the inner side of the frame. 

The prints are very light weight and I suspect that will be a challange if not taken care of. Even if I find appropriate metal wheels I will probably have to add weight to make the wagons run well on my prototypically bad industrial railway track.

A look into the tub. There is no detail on the tub's inner surfaces. I will decide if I fill the tubs with a load or fit detail to at least the upper inner surfaces.

A tub seen from below. The rivets are nicely done.

From this view the tub's riveted construction is clearly visible.

I have ordered brass piping with an inner diameter of 3 mm to be used as bearings and 3 mm axles. That should enable me to test the printed wheels on my track and find out if metal wheels are a must. 

Have you similar wagons in service on your 16 mm railway or any advice on where to find 15 mm diameter curly spoked wheels that will match the skips? Please leave a comment or e-mail me at


  1. Claus, the closest wheels I can find in the UK are Slaters Plastikard ref. 1612DIN. Which are 16mm diameter and six spoke and according to their website, only come with axles suitable for outside framed wagons. However, some kit manufacturers seem to be able to get them without axles. Price for wheels on axles is more than each U skip kit unfortunately!

  2. Thanks a lot for your helpful pointing to the Slaters wheels. I will be exploring them in greater detail and consider a purchase. Fortunately it doesn't matter much if the wheels are the same price as the wagons. I am not a frequent spender of hobby money, so when an investment is necessary the funds are usually available.