These are the ones I know of. A few lack any proof or documentation, but are the subject of consistent, deeply embedded legend. But most are clearly documented in magazines that I have. To list them, I am recalling them from memory rather than going back to look them all up.
An ancient 4-4-0 recovered by a private party from the Suwannee River in Florida 20-30 years ago. Engine was last owned by a logging company and was submerged, but not entirely buried in the bottom. Engine dates from the Civil War era.
A B&M 4-6-2 in ocean water relative to a bridge derailment. Engine lies on the bottom and has been accessed by divers.
A Rock Island 1890-era 4-4-0 in the Cimarron River in Arkansas relative to a bridge derailment. Engine is buried in the bottom. The railroad is still active, and has blocked efforts by others to reclaim the engine because of the threat to the bridge footing.
One or more trucks of passenger F units in Granite Lake, in Montana, where the North Coast Limited tipped over on a curve in 1960s.
A 4-4-0 and several flatcars inside Church Hill Tunnel in Richmond, VA.
Two identical “Planet” class 2-2-0s side by side in the Atlantic Ocean off the coast of New Jersey. Engines were apparently new when lost at sea from a ship, and will be recovered by the New Jersey Museum of Transportation.
Two AT&SF engines (a 2-8-2 and other similar size) mostly buried in a river (Kansas??). Engines have been exposed by low water occasionally and some iron was cut off for scrap. Photos appeared in magazine.
Two engines sitting in the forest of northern Maine having been abandoned after a failed railroad project. Engines are very difficult to access, cannot be reached by road, so were never scrapped. Both are 1910-20-era engines eight-driver wheel arrangements. Have recently appeared in magazines such as TRAINS.
A 0-4-0T buried in an active railroad fill across Shady Oak Lake, Hopkins, MN in 1913. Also a Caterpillar rubber-tired, motor scraper buried in bottom of same lake along the fill for Shady Oak Road in 1967.
An unknown, undocumented engine in Mud Lake, Hopkins, MN relative to an M&StL trestle crossing. Legend passed down through company employees and local residents. Magnetometer pinpoints approx. 50 tons of iron buried in lake bottom.
An unknown, undocumented engine or “train” in Devils Lake, Pine City, MN along the “Skally”/NP/St.P&D/LS&M rail line. Legend passed down by local residents. Newspaper, in 1880s, reports shifting ground at Devils Lake, and consequent peril to the railroad. Divers reported seeing boxcars in lake. Lake is over 80 feet deep with the rail roadbed on a high fill skirting the west side. The fill was originally a trestle over open water.
An unknown engine buried just west of Dunwoody Institute in Minneapolis, MN relative to a derailment. Legend widely known among local residents, but no documentation available, but presumably, the event occurred in the relatively early railroad era. This area, known as the Bryn Mar location, is notorious for soft ground.
An unknown locomotive possibly in the Monocacy Quarry in Pennsylvania. The contentiousness that has attached to this legend will probably forever preclude confirmation.
In the filming of “Ring Of Fire” approx. 1963, a wreck was staged with a logging engine and several passenger cars. They went down with the collapse of a burning trestle, and are still there in the mountainous ravine. It was somewhere in Oregon or Washington. I believe the engine is an 0-6-0T. The event was covered as a news item in TRAINS.
A Kansas Pacific engine lost in Kiowa Creek (Colorado??) relative to a bridge collapse during a flood. For several days following, the engine was submerged, and buried, with its exact location unknown. As work progressed on the bridge and general clean up, the engine was located and recovered. Apparently, (my theory) the temporary unknown whereabouts of the engine took hold as the seed for the local legend that the engine was never found. Ten to twenty years ago, Author Clive Cussler mounted an ambitious search based on that legend, but failed to find the engine. Subsequent research by others has proven that the engine was recovered shortly after the wreck. Cussler attributed the faultiness of the legend to an assumed insurance scam by the Kansas Pacific RR whereby the engine was recovered in secret, at night, without the knowledge of the local people who had presumed it forever lost and never learned otherwise. I doubt that theory.