Nick Russell-Pavier, author of The Great Train Robbery: Crime of the Century, told ITV News there are "two Ronnie Biggs".
"There is the sort of cartoon character who featured in The Sun and doing videos with the Sex Pistols, and there's the small-time thief who was catapulted into the extraordinary tale," he said.
Author Mike Gray, who has written numerous books on the Great Train Robbery and on Ronnie Biggs, said he was sad to hear of his passing as "he has become part of my life and myself part of his."
Mr Gray, whose books include Ronnie Biggs: The Inside Story, said he visited Biggs every month for eight years while he was held at HMP Norwich and HMP Belmarsh.
He said: "He was never a bad person. His criminal CV was laughable before the train robbery and none of the train robbers wanted him on the robbery as they had never heard of him.
"He was only invited as mastermind Bruce Reynolds was Biggs' best pal and Biggs knew a retired train driver. Biggs always regretted the injury to [train driver] Mr Mills."
Ronnie Biggs and his son Michael were interviewed in August at the memorial of Bruce Reynolds, dubbed the mastermind of the Great Train Robbery.
Michael Biggs told ITV News correspondent Simon Harris his father still had very clear memories of the robbery as he was "blessed with a photographic memory".
Asked how important it was to remember the heist, he said "Crime is always wrong so that should be at the top of everyone's agenda, however it is part of British history now ... that can't be changed."
Following the death of Great Train Robber Ronnie Biggs, the Transport Salaried Staffs' Association tweeted:
In case today's media confuses you: attacking railway staff with an iron bar to the extent they're barely able to work again really isn't OK
General secretary of the train driver's union Aslef said although they feel sorry for Ronnie Biggs' family, "We have always regarded Biggs as a nonentity, and a criminal, who took part in a violent robbery which resulted in the death of a train driver".
Mick Whelan said, "Jack Mills, who was 57 at the time of the robbery, never properly recovered from the injuries he suffered after being savagely coshed by the gang of which Biggs was a member that night."
Mr Mills died a few years after the Great Train Robbery took place.
Ronnie Biggs was last seen in public at the memorial of Bruce Reynolds, dubbed the mastermind of the Great Train Robbery, which took place in August.
Peter Rayner, former chief operating officer of British Rail, has been critical of Ronnie Biggs in the past, but expressed sympathy for his family.
Mr Rayner said:
My view is that whilst I was - and am - critical of the Great Train Robbers and the heroes' welcome they got, especially in light of the death of Jack Mills, my sympathies go out to his family and I would not wish to speak further on the subject.
Ronnie Biggs was on the run for 35 years after escaping from Wandsworth prison and making his way to Rio de Janerio.
Here are some of Biggs' more memorable quotes from his time on the run:
"One report said that since my time on the run I've had 2,500 girlfriends. I mean you got to realise, I've been on the run for more than 30 years, I have got to have had more than that."
"There's a difference between criminals and crooks. Crooks steal. Criminals blow some guy's brains out. I'm a crook."
"It has been rumoured that I was the brains of the robbery, but that was totally incorrect. I've been described as the tea boy, which is also incorrect."
"I don't have any intentions to return to England. I would go back if I could return as a free person. I don't want to return to prison."
"I am no longer a criminal. I gave up that practice years ago.