Stress Questions

[gnomygnomy.livejournal.com]

I'm translating a poem by Alexandr Blok, and in addition to a couple words I need help with, I have quite a few where I can't guess the placement of the stress. The poem is На железной дороге.

What does "некошенном" mean? And where is the stress?

изнемогая?

вынуто?

кинуто?

раздавлена?

And I'm trying to make sense of the following verse:

Так мчалась юность бесполезная,
В пустых мечтах изнемогая...
Тоска дорожная, железная
Свистела, сердце разрывая...

"So (useless?) youth sped along,
exhausted in empty dreams...
Iron-road melancholy
whistled, breaking off the heart..." ??????????

Any help is appreciated! Thank you. :)