Use a good sized digger on heavy tracks.

If no luck you may have to dig the trench out.
It is very likely that the conduit is broken somewhere and filled up with debris hence the cables are stuck.

or ?

a hidden junction or repair was done in the past in open soil and backfilled which makes it almost impossible to get the cable out.

Please let us know what the outcome is.

Thanks

The product of rotation, excitation and flux produces electricty.