Steel belted tires as Soft Subgrade improvement

Surely in the long history of railroad engineering someone has proposed to recycle steel belted automobile tires to improve the subgrade in soft soils. I see a similar idea pop up from time to time as a means to stabilize the soil in slopes. Of course various railroads are either using hot-mix asphalt or geotextiles to improve the track structure during major reconstruction.
Has anyone heard of a current product or failed attempt to turn automobile tires into a sort of mat that would prevent the migration of fines into the ballast while improving the track modulus?
Virgil Payne

Never heard of it and suspect the EPA would not allow it for obvious reasons.

The use of "tire chips" for highway subgrade has had mixed results including release of toxic substances and the material catching fire! Here is a link I found that discusses the problems:

http://www.metrokc.gov/procure/green/rubber.htm#13

I was thinking more in the line of taking the tread portion of the tire and cutting it once so that a strip is left. Mats of several strips stapled together would set just below the ballast, preventing the soil from moving into the ballast and providing a layer with the capacity for tensile stress.