Mr Anderton had been in a critical condition in Dunedin Hospital's intensive care unit, and news of his accident had left the Otago racing community reeling.
Otago Racing Club chief executive Andre Klein yesterday said the 43-year-old trainer was among the ''backbone'' of the Wingatui racing community and one of the most respected young trainers in New Zealand.
''Steve is regarded as one of the most professional trainers and a great bloke as well, a really, really good guy.''
It was a ''dark day'' for the close-knit racing community, he said.
Constable Jason Braid, of Mosgiel, said emergency services were called to stables in Wingatui Rd about 6am yesterday after Mr Anderton was found by his colleagues, seriously injured and trapped under a horse truck ramp.
Const Braid said the ramp was hinged to the truck and served as a door in an upright position.
The ramp hydraulics appeared to have ''malfunctioned'' when Mr Anderton was preparing to lower the ramp to load horses to transport to Wingatui Racecourse for training.
When the ramp was upright, it was secured to the truck in that position by a steel latch.
Usually, when the latch was opened, the hydraulics held the ramp in an upright position, he said.
However, it appeared the hydraulics failed and the ramp ''dropped'' when it was unlatched.
The truck was owned by Mr Anderton and no horses were injured, Const Braid said.
Mr Anderton was taken to Dunedin Public Hospital by ambulance in a critical condition, he said.
WorkSafe NZ was investigating.
Mr Klein said Mr Anderton came from a ''long line of respected horse trainers'' including his father Hec, grandfather Hec and his uncle Brian Anderton.
The website for NZRacing, the national regulatory body for race clubs, said since the 2002-03 season, Mr Anderton had trained 167 winners, 88 of which were in partnership with his father Hec. Horses he has trained have won more than $2.3 million.
Mr Anderton is a regular winner of the Otago trainers' strike-rate award, which is worked out on a starters-to-winners ratio and has struck up a good association with the breed established by the Dennis brothers, of Woodlands.
Top horses he has trained for the four Dennis brothers include The Solitaire, The Glitzy One and The Diamond One.
The latter was the favourite for the White Robe Lodge Handicap at Wingatui on Saturday, which has been rescheduled to Friday after the meeting was abandoned.
Mr Anderton and his father were trainers together for six seasons and experienced success at the highest level in racing when they trained The Jewel to group 1 (prestige) wins in 2002 and 2005.
His family has asked for privacy and will be making no public comment.
