Mr Grayling defended the project as necessary to tackle the growing capacity problems on the existing rail network.
The departure of David Cameron from Downing St and the unpopularity of the HS2 project among some Conservative backbenchers led to suggestions that Theresa May could scrap it.
But Mr Grayling’s comments suggest HS2, which will serve stations in Sheffield, Leeds and perhaps a further parkway station on the M18, will continue under Mrs May’s administration.
He said: ““I have no plans to back away from the HS2 project.
“And the thing that’s important for people to understand is that HS2 is not simply a speed project, it’s a capacity project.
“We have lines at the moment which have seen huge increases in the number of passengers, the amount of freight in recent years.
“The West Coast mainline for example is becoming really congested, it’s limiting the capacity of services to places like Northampton and Milton Keynes.
“HS2 has always been a capacity project as much as a speed project.
“Of course it makes sense if we’re going to build a new railway line for it to be a fast railway line, to increase travel times or reduce travel times from north to south, that’s logical.”
Business and council leaders in Yorkshire are also looking for assurances that the current timetable to agree the route and station locations through Yorkshire as part of phase two of HS2 will be met.
Services are due to start in around 2033.