I refer to the latest post by Father Finnigan here where he discusses the removal of a front temporary altar.
When I first came to Barnard Castle in November 2001, the sanctuary of St Mary's had been 'modernised' a few years previously: the altar rails had been taken from their proper place and fixed to the lowest step of the gradus, the floor was raised by a platform covered in a green carpet and projected out towards the nave; otherwise no changes took place. Except of course that a front altar was put in place (I understand that the altar was made from the recycled pulpit and confessional - the confessional was one of those with a curtain shielding the priest and penitent where everybody could hear what you confessed and the penance which you were given!)
Then we took the rails and put them back in their proper place, so that the space on the sanctuary is what it used to be, and on occasion, for traditional weddings, we can bring them forward to create even more space for ceremonies.
The mechanism for moving the altar is not patented, and I am sure that Joe would be pleased if someone decided to copy his handiwork!