The Le Roy Marion
The world’s largest steam shovel surviving intact is a 1906-built Marion machine, located in the small American town of Le Roy, New York. 

This machine was bought by the General Crushed Stone Company, who operated the largest rock crusher in the world at a quarry in Le Roy. The shovel, which weighed over 100 tons, was originally mounted on flanged rail-wheels, but was converted to caterpillar tracks in 1923 using a conversion kit manufactured by Marion. 

A crew of three men were required to operate it: a fireman, who kept the boiler fed with coal and water; a crane man, who sat on the left-hand side of the boom and tripped the 1 5/8 yard bucket by tugging on a wire rope attached to the bucket; and an engineer (or driver), who raised and lowered the bucket and drove the machine along the track.

This shovel remained in use until 1949, when it was driven out of the quarry and parked by the main road – where it remains to this day, although no longer functional. The Town Council have purchased the land on which it sits, and are planning to apply (in March 2007) for National Landmark status for the shovel. 

Note: The shovel and land are now a historic landmark.
So it should be preserved now for posterity.

They were considering moving it to alexander NY to the site of the Alexander Gas and Steam show. Maybe a 20 mile trip, but nowadays an impossible route due to height, size, and weight.
More info:
Made Marion
by Lynne Belluscio
We almost missed the 100th anniversary of “Marion” the steam shovel on the Gulf Road. The 1906 Le Roy Gazette reported that the 100-ton steam shovel was manufactured in Marion, Ohio for the General Crushed Stone Company, which in 1906 operated the largest rock crusher in the world. The company needed a shovel to load stone from the quarry into the small railroad cars that conveyed the large stones to the crusher. The steam shovel was known as a 5-yard dipper. Originally, when the Marion came to Le Roy, it moved on railroad tracks, which had to be laid in the bottom of the quarry. A crew of men relaid the tracks when the shovel moved to a new rock face.
In 1921 the Marion Company manufactured a “kit” to change the railroad wheels to caterpillar tracks but it wasn’t until 1923 or ’24 that the Le Roy shovel was adapted to caterpillar tracks. The Marion shovel worked in the quarry for forty three years and in June 1949 it was driven out of the quarry by Manny Stefani and parked near the edge of Gulf Road where it is now. One of the locomotives and a tip car were displayed with it. (Several years ago, General Crushed Stone gave the “Dinky” to a collector near Syracuse and it was moved, much to the dismay of all the people who had worked in the quarry!)
The Le Roy shovel is called a partial swing shovel since it doesn’t move 360 degrees. The main frame is mounted on two all-steel heavy-duty trucks (sometimes called bogies). The axels are driven by chains and gears from the main, reversible engines on the deck of the shovel. The power for the equipment is a locomotive-type boiler with reversible hoisting, swinging and thrusting (or crowd) engines.
The Le Roy shovel has the original Marion boiler, although it is not in operating condition. The lower flues are badly rusted and the doors are broken. Attached to the front of the frame, or car, is the swing circle, on which is mounted the excavating equipment which consists of the boom, the dipper handle, the dipper and the thrusting engines. Unfortunately the thrusting engines are mounted on the boom and have been exposed to the weather and are full of water. The other two engines seem to be in working condition. The boom is split which allows the swing of the dipper handle. The dipper is made of heavy steel plates and the teeth are made of manganese steel. Kermit Arrington told me that his father often removed and sharpened the teeth.
The steam shovel was invented by an American, William S. Otis in 1836. It was the first efficient dry-land single bucket excavator and was a partial swing machine, like the Marion in Le Roy. The full swing, revolving shovel was introduced in 1884 in England. The advantages of the revolving shovel was eventually recognized and the railroad shovel was doomed.
Although it has been rumored that the Le Roy Marion had been used to dig the Panama Canal, that is not the case.

source:  HAMB