How old does this wreck look?

I don't think it's from the same wreck.  That's a roller bearing truck in the foreground and while RB trucks were around in the 40's, they weren't in wide use.  Also the underfame isn't from a passenger car, looks to be from a flat car of some type.

I would guess the wreckage is anywhere from the mid 60's on up.

Rusty

That is a freight car truck--doesn't look like anything you would see under a passenger car.  The only passenger cars I can think of that used freight trucks were WWII troop cars that were similar in construction to box cars, and they didn't use roller bearings.

The bulkhead on the left end of the picture looks to me to be an end of a lumber load car..

When the Great Salt Lake was raising so fast the railroads could not keep up with it, the SP dumped a lot of freight cars in the lake to try and stop the wave action from eroding theIr fill. This was in the mid 1980s. There were miles of these cars along the south shore of the causeway. It would be unlike a railroad to not pick up all the big pieces after a derailment, so I am pretty sure these car parts are here intentionally. 

During this time the Western Pacific tracks around the south end of the lake were raised 12 feet.  Eventually the Southern Pacific got a contract to pump the excess water out of the lake.  I believe they a contracted with MK to build a pipe line to the west toward the Bonnieville area and managed to reduce the lake level after several years of pumping.

On one trip across I80, which runs just south of the WP, the only part of the highway that was not under water was one shoulder. East and west bound traffic alternated driving on this shoulder while the highway department tried to raise the driving lanes. This went on for maybe ten miles.  The highway had the advantage of being separated from the lake by the WP, so it did not have the wave action to deal with.  

Actually the state of Utah bought three pumps and installed them in the West Desert, they ran for a few years with minimal effect on the lake. In fact by the time the pumps were built the lake had started going back down. What saved us was several dry years.

The pumps are still out there, high and dry and will probably never be used again. Us Utah taxpayers got stuck with a bill to bail out companies that should have paid for it themselves (The pumps are still a sore issue in Utah). The lake itself is super low these days.

I do agree that those cars are newer and like you I cannot see the RR leaving remains behind especially remnants of a major fatal accident

Interesting.  Thank you for posting the details.  I have flown into Salt Lake City and tripped north to Wyoming and the Grand Tetons.  You never really consider that a lake level can change, but in recent years there has been concern also about lake level in the Great Lakes/Lake Erie.   Salt Lake area is one beautiful part of this country.

The lumber in the photo is engineered lumber, an I-beam built out of wood.  That is a recent product.  Maybe no more than 30 years.

I used to drive semis back when the Salt Lake was rising. Chicago to LA or San Francisco & back was my weekly run and I remember driving I-80 when they were raising it and the rr that ran along side. Took I-80 when heading to the "Bay" otherwise we'd cutoff I-80 onto 189 and head southish to Provo and jump on I-15 to LA.

Beautiful country out that way! Can over the road semis still drive on 189??

Yes 189 is still open to semis

Chris I would say you don't look a day over 39... should not put yourself down like that...