I.m planning my transitions from the mainline and noted that the “spur” has a lower place in the pecking order than the “siding”. What is the difference?
BB
A siding is a double ended secondary track for trains to pass. A spur is a dead end track serving an industry or lots of other things.
What source led to your concluding that there is a pecking order, Bruce? I am not aware of such an order, but if you mean that the effort to install and to thereafter maintain, then I suppose the siding, if it is used often, might get more of the above. However, a spur, even if of relatively short duration, say 6 years or so, may have lots of revenue-bearing traffic. If it is heavy traffic, but still only rates a single-track spur, then maintenance would be a serious undertaking.
If you meant in terms of ballast and the level of the rail heads relative to the adjacent main, or even in terms of rail weight, then the main would get the nod.
Sidings are often lower at the rail head in order to prevent parked cars or trains from inadvertently rolling into a switch leading to the main, and fouling the main.
A siding (which may be single or double ended) is intended for use by full-tonnage mainline trains and locomotives, and must be built and maintained accordingly. [I know of one siding with two stub ends that is (approximately) level. It crosses a steeply-graded single track main to which it is connected by a double slip switch! Trains stopping for a meet or pass take siding through the curved side of the DSS, then back across the main and hold. Once they have clearance, the upgrade-bound inferior train has a hundred meters or so of level track on which to get rolling before tackling the 2.5%. The double slip was between a bridge abutment and a long tunnel bored through not too solid rock.]
A spur is a single-ended track serving an unloading spot at a freight house, team track or industry. Construction and maintenance standards are determined by the weight of cars to be handled. [One spur I railfanned a half-century ago was a long, snaky affair that ended up in a small town lumber yard. It was laid with light rail on infrequent ties. A sign adjacent to the main line turnout listed the locomotives that were NOT to use it - roughly 90% of the NYC steam roster. A little farther in, but still well short of the lumber yard, was another sign - “No locomotives beyond this point.”
Including that in your operating rules might add a bit of spice to handling a way freight.
Chuck