Sarapva, yes, they are cherry trees!
This is an aerial photo that had been published in the Asahi Shimbun in 2003:
The article says that it was created in 1999, in time with renovation of Odakyu Electric Railway's Kitami yard and in response to the call from Tokyo Metropolitan Government to promote "rooftop greenery" in the city. I remember the time when it was still brand new, and the trees didn't look like it will grow any bigger...
The park is on the right side of the stream and is roughly 27,000 sq.m. in size. The buildings on the left make up an exclusive condominium complex. The developers of the complex also complied with the government and created gardens on top of the condos.
The following are photos taken on the same day, from the stairs that lead up to the park and looking at the cherry trees that line the stream (called Nogawa River).
The view of the condo complex behind the trees:
The view of the stream from the same spot but looking in the opposite direction. I think you can identify in this photo the light-blue colored bridge in the news photo:
Yes, I will try to take photos of the depot itself (possibly with a view of the trees on top) the next time I pass by the place!
