The phrase "a state coach" is correct and usable in written English.
It can be used to refer to a coach or carriage that is used for official state functions or ceremonies, often associated with royalty or government officials.
Example: "The queen arrived at the ceremony in a beautifully decorated state coach, drawn by a team of magnificent horses."
Alternatives: "royal carriage" or "official coach".
He was accorded the honour of riding with the Queen in a state coach to Buckingham Palace.
"It's not as if I have a choice," said a 23-year-old Eritrean boarding a state coach to central France.
Among the jewels, tiaras and other beauteous artefacts that have to be given, there was a state coach made out of chocolate.
Their Majesties rode from Buckingham Palace to the House of Lords in a State coach drawn by a team of eight cream ponies and attended by escorts of the 1st Life Guards and Yeomen of the Guard.
Kate Middleton, it has been disclosed this month, will ride to her wedding with the future King William in a mere motor car, only to be transported away at the end in the shimmering glory of a state coach – symbolising her transformation from commoner to iconic ingredient in the topmost rank of British society.
The swirl of colors, the marching bands, the deafening roars, the over-the-top political incorrectness -- Florida State's Seminole mascot riding in on horseback; a Mississippi State coach some years back, on the eve of a game against the Texas Longhorns, castrating a bull.
It was the first time a Penn State coach was voted the Big Ten coach of the year, as DeChellis was by members of the news media.
"While the Chinese president is riding down the Mall in a gilded state coach British steelworkers are being laid off," Labour's Kevin Brennan told the House of Commons.
Like so many of my generation, the first programme we watched was the Coronation, and we were given a miniature state coach and horses by way of celebration.
He is currently managing or has recently completed five others, including one for the collapse of the stage at the Indiana State Fair and one for the young people molested by Jerry Sandusky when he was a Penn State coach.
While the Chinese president is riding down the Mall in a gilded state coach, British workers are being laid off because our government is not standing up for them".
