Yard Ballast

I have been studying prototype railroad yards more many years trying to figure out why most all model railroad yards don't look real to me. My friend Joe Balint pointed out years ago that most modelers use track ballast that is to coarse or ( large ) for the scale they are using. It seems to me that this is often a recommendation problem with the ballast supplier where they suggest using their "fine" size ballast for N scale,"medium" sized ballast for HO and "large" for O scale track. Model Railroader has also done this over the years with their project railroads where they recommend Woodland Scenics medium sized ballast. I guess a lot of modelers just take magazine and/or the suppliers word for it and throw it on their models and don't even look to see if the ballast looks right. I have always used the finest ballast I could buy and while it helps things look better but it’s not all that's needed.
   Lance Mindheim pointed out on one of his blogs that uniform color and size is another problem with most modeler’s ballast. Using a blend of different sizes (fine and extra fine) and similar colors (light grey and dark gray) also help improve the look of modeled track ballast.
I know a guy named Jack, he has a model railroad of the Monon in the 1950's and years ago I was part of the crew that helped build and scenic the railroad. When it was time to put down ballast he brought out two big coffee cans of ballast he wanted us to use. One had plain black ballast in it (cinders), this was to be used in the yards and industrial sidings. The other had a blend of black (cinders) and white (limestone). It looked like salt and pepper mixed 50/50. The blend was for the mainlines. Jack explained that the Monon like many railroads had ballasted the track with cinders. But in the late 40's the Monon started buying limestone ballast from the local limestone quarries.

 The blend of ballast tells the maintenance history of the track, that is one of missing parts of track ballast that didn't look right but I didn't know it then because the technique Jack used wasn't quite right. Jack just mixed the two different colors together 50/50 or 70/30 before applying the ballast. However, when railroads add ballast and tamp the roadbed, the process doesn’t neatly blend the old and new ballast. The only circumstances’ where I have seen old and new ballast truly mixed together is where the railroad has done substantial digging into the roadbed. Two examples would be cleaning up a derailment or substantial track replacement like an entire switch in a yard ( ties and all ). Otherwise the newest ballast should be on top of the oldest ballast with only a little mixing of the two ballast types resulting from the tamping process. Just how much of the old ballast can be seen layered below the newer ballast is a function of two things that I can think of. 

1. How many maintainance cycles the old or new ballast was brought in from a particular source.
2. How much ballast was applied during any given maintainance cycle. 

So if you were to cut away a section of the roadbed of a prototype railroad, you would see fairly distinct layers of ballast with only a little blending if any between the layers.
The last of the missing pieces that I can think of is track weathering. Their are many sources of track weathering and much of it has to do with the commodities the railroad is transporting. The most obvious examples would be coal vs. Iron ore. You would expect the coal hauling railroad to have track tinted with fine black coal dust and an iron ore hauling road the have track tinted with rusty looking dust. Additional cargo sources could be woodchips which blow out the chip hoppers then turn color as they degrade in the ballast or sand, salt, or grain leaking from passing freight cars.

Another source of weathering is related to how well maintained the ballast is, I've heard it call mud pump. It occurs when the ballast clogs up with dirt and silt and then doesn't drain. As trains roll by, the track (including the ties) flex up and down which "pumps" the mud up between the ties and this gets splattered all over everything. I don't think I have any photos of this but if someone can send me one, I'll add it to the blog as an example.

The last source of track weathering is something that I have not encountered my self because it's mostly before I go into trains. A good friend of mine told me about how lube oil from the friction bearings on freight and passenger cars would sometimes spray out onto the ballast. Apparently this only happened to the ballast outside of the rails and when dust and dirt from everything else was added, the roadbed acquired an asphalt like color. Again I need to find some photos of this.
           
Next I have some photos of some of what I wrote about. I have not yet finished all the weathering of the track and rail, I’ll have to add those photos later.

Above we have a good example of the size difference between cinder and stone ballast. The area bounded by the bright green lines shows some stone ballast added to the cinders when the maintainance gang had to do some work on the diamond.

The next image shows the older cinders with the newer stone layered above. There is also a variety of colors of stone ballast here. The track nearest the utility pole shows a substantial amount of newer stone ballast suggesting major track work, while the track just below it shows more targeted maintainence as well as a different color stone.

This image is just to the right of the previous one and again shows some blending of cinders and stone ballast but the blend is not consistant. The track with all the stone ballast is the yard throat and the main runaround. As a result, this track was built 1/8" higher than the rest of the yard in addition to the newer stone ballast. What I'm modeling here is the area of the yard that had major maintainance and track realignment. The track then drops into the remaining yard that is mostly still ballasted with the older cinders.

Here is a side view of the previous area. I hope you can see how the track drops from right to left.