RRSignal made some track similar to that which might be helpful, though, the ties show on his, but his track is sandy.
There is also some rusty standard gauge track available in some routes from Jointed Rail. I'm not sure if it's available separately.
<kuid2:45324:38033:1> JR NS yard 1. Yard 2 has ties with grease in the middle with rusty rails.
There are also a number of tracks by samplaire which might be useful as well.
<kuid2:132952:100163:1> SAM Track - Overgrown v1 NO 3D SCREW
<kuid2:132952:100164:1> SAM Track - Overgrown v1 RUSTY NO 3D SCREW
<kuid2:132952:100571:1> SAM Track - overgrown RUSTY v1
<kuid2:132952:100596:1> SAM Track - overgrown v1
<kuid:132952:131585> SAM Track - overgrown RARE USE v1
<kuid:132952:131587> SAM Track - Overgrown v1 RARE USE NO 3D SCREW
These have grass in the sleepers, however, and not sand. I suppose you could always change the textures if you want.