Ballast on railroads with heavy steam locomotives

[J.Rob]

I have read somewhere about the change in ballast after the 2-6-6-6 was placed in service. The change I am referring to is at the end of the ties. Pre 2-6-6-6 the ends of the ties were exposed for better drainage, after, ballast was generally level with the tops of the ties past the ends of the ties. My question is how would this allow the ties to carry more weight from the heavier locomotives? Did this occur on all both the Virginian and the C&O? Any comments would be helpful I am sure.

[henry6]

Can't quite follow your question, J.Rob.  But steam locomotives not ony place the weight of the locmotive on a given rail segment, it also "pounded" or slammed any given rail segment with piston thrusting downward on alternating sides.  So rails would push ties deeper and deeper into ballast and push ballast at end of ties outward away from the track lessening drainage capabilities.

 

[selector]

For properly contoured ballast, for the ends of the ties to be exposed means there would be something close to a 45 degree angle of the ballast running from the top surface of the tie diagonally across the sides of the ties and on down to the sub-roadbed.  This necessarily means the outward 8" or more of the top edge of the sides of the ties toward the ends would be exposed, and so would the sidewall down to the lowest outer lip of the tie.   I am assuming a near-perfect situation of the type you seem to be suggesting.  So, this leaves a significant portion of the tie ends frictionless and unsupported or restrained.  An engineer may have demonstrated that adding a bit more ballast to bolster the 'shoulders' would add just enough restraint to the ties to permit safe passage of an H-8 working hard at the head of a coal drag.

That's my best guess.

Crandell

[rrboomer]

I would suspect that heavier rail to support the larger steam locomotives may be the reason.  The larger rail has more mass to expand than lighter rail, so perhaps hot weather horizontal track movement was becoming more of an issue along with different dynamics of articulated engines and increased slack action from longer heavier trains.  I readily admit I am not a civil nor mechanical engineer.  As a locomotive engineer I've seen the problems longer, heavier locomotives, cars and trains cause with the track structure.

Dick.