Wood ties vs. Concrete ties.

[CShaveRR]

If the wooden ties are still in decent shape, they'll be recycled by the railroad--reused in places like yards.

I'm sure Mudchicken will be able to enlighten us on the ways that worn ties are disposed of these days.

There is, or was, a fleet of old coal gondolas running around with reporting marks WWEX--for Wood Waste Energy. That's one possibility, once a number of environmental issues have been cleared.

[Leon Silverman]

Cannot tell you what is done with old wooden ties. However, pressure treated wood still deteriorates over time if it is buried in the ground. The flexing of wooden ties you mentioned is NOT desireable for trains. If this was so. you would see suspension bridges used on heavy duty railroads. The various designs currently used are intended to provide an unyielding support for the track and trains.
Poured concrete block does, indeed, have very little strength. However, prestressed concrete can support tremendous loads because the concrete always sees only a compressive (where it is extremely strong) load. This is accomplished by stretching the rebar prior to pouring the concrete. Once the poured concrete cures, the rebar is released. In attempting to regain its original length, the rebar now compresses the concrete block. The block will now not crack unless the generated bending moment force exceeds the residual compressive force.

[Anonymous]

Just last year the Union Pacific had just replaced Thousands of ties on the Blair and Boone subdivisons. After the Wood ties are replaced with Concrete ties,what does the Railroad do with the thousands of older Wood ties right after they have been replaced. Does Concrete last longer than Wood? Why do Railroads use Concrete ties on switch tracks since concrete ties can crack under the extream weight from the constant pounding from a heavy train. I thought that Wood ties would flex much better under the extream weight from the train. I have seen that most track with concrete ties don't flex (bounce) as much as the Wood ties. What gives? Plus with Wood ties,The rails are spiked,on the other hand,Concrete ties are cliped. Thanks,Allan.