Updates to a train of Dapol IOA bulk ballast wagons, sourced "weathered" from Hattons at a bargain price, to be hauled by the Network Rail Class 57/3.
I came across the IOA wagons on the Hattons website and decided to obtain 6 of them to make up a ballast train for my network Rail Class 57/3. I was attracted by the "weathered" nature of the units as in pristine condition I think these wagons look a bit..... well.... plasticky!
However upon delivery, I discovered that the weathering seemed to be based on an assumption that the wagons have been carrying coal for the last few months. The weathering is all in matt black and didn't look at all convincing for ballast wagons.
The matt black was particularly conspicuous on the wheels, where a thick coat had completely covered the metal running surfaces. It is imperative that these are are thoroughly cleaned before they come into contact with my track!
Some research via Google soon identified a number of real IOA ballast trains in various states of weathering. None of the wagons displayed the Hattons black interpretation, but instead, the bogies and underside exhibited the typical greyish brown track weathering, with an additional dusty coating of pale grey ballast dust on all horizontal surfaces and in all cracks and crevices of the body sides. The photos also showed the appearance of the ballast loads in the IOA wagons.
So a programme of wheel cleaning, re-weathering in the correct colours, construction of ballast loads and construction of a flashing rear light on the last wagon, is required.
An example of the weathered IOA wagons, as received.
A lot of matt black in evidence.
Very sooty looking wheels!
Sorting out the paint finish:
The wheel sets were first removed from the bogie frames. The running surfaces were then attacked with kitchen roll, soaked with white spirit, before polishing with dry kitchen roll. After re-assembly, the wagons were run through a Woodland Scenics wheel cleaner for several seconds.
The running surfaces clean up well using white spirit and a good rub!
The matt black weathering on the body was overpainted with pale grey as were the bogie frames, on top of an initial coat of track brown.
Adding ballast loads:
A simple braced load base was constructed from 1mm plasticard, forming a close fit in the wagon. This was topped off by a polyfilla load shape.
After leaving overnight to dry, the polyfilla was painted matt grey. In the foreground is an inverted load showing the bracing arrangements.
When the grey paint had dried, it was covered in neat PVA glue and given a sprinkle covering of track ballast.
When the glue had partially cured, the load was fitted into the wagon and the edge ballast pieces were tidied.
Adding a flashing rear light:
An astable multivibrator circuit is used to generate the 2 flashes per second drive voltage for the red LED. Power is provided by picking up the DCC track supply via wheel contacts to be mounted on the 4 rear bogie wheels. The DCC supply is applied to a full wave bridge rectifier, followed by a reservoir capacitor. The astable circuit makes use of 2 of the large collection of PNP transistors in my components bin. In theory, the base voltage can get high enough to reverse bias the emitter base junctions, so these are protected by additional base diodes.
The flash on and off times are set by the values of the 4.7uF capacitors and the 100k (off time) plus 33k (on time) resistors. The values below give an on time of approx 1/8 second and an off time of approx 3/8 second, resulting in a flash frequency of around two flashes per second.
The circuit diagram
Circuit "rats nest" glued to a plasticard base, sized to fit under the load.
Circuit installed in the rear wagon
New wheel contacts fitted to the rear bogie. (before the new plastic is painted black.)
The original matt black "weathering" was removed before super gluing the phosphor bronze pick-up plasticard fixings to the bogie frame.
Drawing of the rear lamp with scale dimensions
Load in place & a simplified interpretation of the rear lamp, flashing.
All finished!.........a few photos of the complete train on the test track: