Model Rail (UK)
STEP BY STEP
Scale Model Scenery offers three different packs of bulk bags, with and without branding (including Network Rail logos). Supplied in laser-cut kit format, the only tools you’ll need for assembly is a sharp scalpel to free the parts - and tweezers.
The parts are held to the paper backing by small tabs that need to be cut through. Take your time doing this, to avoid damaging the parts, especially the thin bag handle straps. Once freed, place the ‘bags’ to one side as you continue to remove the rest.
Assembly of the bags begins by forming strap handles into loops. Simply fold the straps over and fix to the inside of the bag with a small drop of glue. I used Super ’Phatic glue, as it creates a bond within seconds.
Each bag needs folding to shape, beginning with the retaining tabs. The production process creates discreet scoring, allowing the parts to fold precisely without distorting the bags, which is very impressive.
Small blobs of the Super ’Phatic glue were applied to the tabs with a cocktail stick and the parts were pressed together. The sides feature a slightly convex profile, which needs to be created by gently curving the paper between your fingertips before assembly.
Once you get the hang of assembling a couple of the bags, the task soon speeds up for subsequent bags. Each of the MHA wagons will hold 14 of the one tonne bulk bags, which is well within the prototype’s payload capacity.
To economise on scatter material – and make it easier to bond the loose ballast together – the bags were half-filled with foam, cut from packaging chips so that they would fit snugly within the bags without putting pressure on the glued joints.
Carefully employing a miniature spoon, the bags were filled with fine ballast chippings. For this, I used ‘N’ gauge granite ballast from Geoscenics but would later wish that I had opted for a lighter shade of material, such as limestone.
Gently tapping the corners of the bags will help the fine chippings to settle and, if any gaps appear, a little more ballast can be added. I tried to retain a ‘mound’ profile, rather than a level load, for a bit of extra visual interest.
Fixing the ballast provided something of a quandary. There’s a risk of softening the paper with excess water-based adhesives, which could cause the printed logos to run. I trialled a super-thin cyanoacrylate glue, hoping it would produce an instant bond.
The cyano glue was applied via a pinpoint tip, with just enough of the thin fluid decanted to allow it to run among the loose ballast.
It’s easy to see it making contact, as it darkened the ballast considerably.
Restraint is important, as only a tiny amount of glue is required to bond the upper layer of ballast, while ensuring coverage is even. Work beside an open window and wear a facemask, as the solvent fumes can be harmful.
Not everyone will fancy the use of cyano glue, so I also tried out Ballast Bond adhesive, which is ready to use and dries faster than PVA. Care will still be required to avoid staining or damaging the paper bags.
Again, a pinpoint applicator was essential and the minimum of glue applied, watching as the ballast turned darker, denoting that the glue had penetrated throughout. While cyano cured instantly, Ballast Bond rested overnight.
With both the super-thin cyano glue and the Ballast Bond, the granite ballast retained a darker shade than I’d intended. This, after all, is meant to represent fresh ballast. Next time, I’ll definitely use a lighter limestone ballast.
Before the wagons were loaded properly, they were treated to a weathered finish. Work began with an overall coat of acrylic paints (a mix of dark and light browns), before cotton swabs removed most of the paint.
After working around all four sides of the wagon, the same paint mix was stippled to the interior over two or three coats. This produced a rough, random texture that looks a little strange and messy for now.
The preliminary weathering was then refined with an airbrush, loaded with a thinned mix of Tamiya acrylics. A very fine misting of paint softens the hard edges and strokes left behind by the paintbrush and swabs.
The stippled interior finish was also greatly improved by misting layers of Tamiya paints via the airbrush. Flat Brown, Flat Earth and Matt Black were mixed together to produce a range of weathering shades that were layered over several very light coats.
The same weathering shades were also airbrushed over the ballast bags, to give them a less pristine appearance. When applied in light, misted coats, Tamiya paints dry rapidly, so the bags could be handled almost instantly.
As well as a wagon loaded purely with bagged ballast, I partially filled one with a load of spoil (dirty ballast). A few scrap sleepers and short lengths of rail, plus a traffic cone, barrel and discarded pushchair add extra character.
With the recovered lineside detritus suitably arranged, it was secured with a little Ballast Bond, applied through a pinpoint tip. I didn’t secure the ballast bags, allowing them to be easily unloaded if desired.