The phrase "long staircase" is correct and usable in written English.
You can use it to describe a staircase that has a considerable length, often implying that it requires effort to ascend or descend.
Example: "After a long day at work, I dreaded the thought of climbing the long staircase to my apartment."
Alternatives: "extended staircase" or "lengthy staircase."
Running up the centre of each face is a long staircase; all four are given equal importance.
We climbed up a long staircase stamped with images of Hindu gods used to deter unsanitary behavior.
By the time the group had ascended the building's long staircase to the third floor, Cox was winded.
Ascending the long staircase leading to the walls, I paused and looked back down the hill at a sign reading, "You Are Now Entering Free Derry".
With an arm draped around his caddie, Mike Cowan, known as Fluff, he ascended a long staircase and walked to a small area where he met with reporters.
The view from the top of the jump, which is reached by a long staircase, is a peaceful vista of Salisbury's little streets and farms.
I've been doing stuff on staircases - really long staircases - going down with my hands and legs, going down with my hands first".
Fortified by the caffeinated rocket fuel, we made our way north along Silver Lake Boulevard and eventually up some long staircases and winding streets to the perfect spot for watching the sunset over a line of graceful palms shimmering in the distance.
One 40-foot-long staircase section has buckled as if stomped by a giant.
But as I squeezed down its musty, curling, 20-foot-long staircase I was equally ready to believe Orkney myth, which says it was the lair of "trows".
Our dynamic performance-monitoring model (DPMM) unifies a variety of psychophysical data on transfer of PL, such as the short-vs-long staircase effect, as well as several findings from the double-training literature.
