Ceci n'est pas une pipe...
But they have nothing to do with Magritte.
I dug up these clay pipe bowls in the garden some time ago. I don't know how old they are but they're likely to be at least 100 years old. Clay pipes fell out of favour in Edwardian days, after their use became associated with cancers of the lip. Apart from being a Christian symbol of Saint Peter I don't know the significance of crossed keys. The castle with three turrets, surmounted by a crown, is the badge of the 27th Inniskilling Regiment of Foot (later the Royal Inniskilling Fusiliers).
The regiment was raised in 1689 as a local militia: Zacharaiah Tiffin's Regiment of Foot.
Stomping on the Catholic Irish—supporting James II—on behalf of the Protestant William III, especially at the decisive Battle of the Boyne in 1690, Tiffin's lot helped throw a log on a fire that burned until the Good Friday Agreement of 1998 and may yet, thanks to Brexit, reignite.
In similar vein (stomping on local populations with the temerity to both stand up for their own rights and support other claims to the [by then] joint Crowns of England and Scotland), the regiment saw action at Culloden in 1746, where the English left a similar impression on the Scots as they had on the Irish. Brexit, again, is likely to provide the propulsion for a still resentful Scotland to (less violently) secede from the Union.
In 1751 the regiment became the 27th (Enniskillen) Regiment of Foot, and in 1775 they were mobilised in the American War of Independence but, due to American and French alliances, spent their time in expeditions in the French West Indies.
Come the Napoleonic Wars, the 27th were notably involved in various battles and were at Waterloo. They weren't waiting for a train.
After that, they went to stomp on yet more locals in the Xhosa Wars of South Africa and in the Indian Mutiny. During this period, they changed their name from "Enniskillen" to "Inniskilling", whether that was in an effort to disguise themselves or to introduce the more appropriate "killing" suffix to their title I couldn't say. Possibly neither.
In 1881 they became the Royal Inniskilling Fusiliers, after merging with the Madras Infantry, so at least they'd never be short of a curry.
It's amazing, the information contained in one small, found object.