I don't have any figures to back it up, but based on my unscientific sampling of KCSM track down here (where I've had a chance to railfan) I'd guess that KCSM has between 50-75% of their track with concrete ties, probably close to the upper end of that range. And It seems that they continue to work replacing wood with concrete as they do maintenance. I'm lead to believe that most of their N-S mainline from the border to Mexico City probably has concrete ties. But last time I saw them, the branches to Tampico, Veracruz, and Acambaro had wood ties, at least in the sections I saw. Don't know about the branch to Matamoros. I think the branch between Celaya and the port of Lazaro Cardenas also has concrete ties. Regards Ed
Thanks Ed. :tb-biggrin: I asked this question because I know KCS is using concrete ties on the new line between Victoria and Rosenburg but the only KCS track I have been exposed to is the line between Laredo and Corpus Christi (former Tex-Mex line) and all 167 miles of the line has wooden ties still.