This is a frequent D3D Hung crash, similar to [Link Removed] and [Link Removed].
A potential fix for the other crashes was released in 4.14.2, but this crash is still occurring on that release.
Stephen - Repro steps currently unknown. I did experience this once on my home PC after dragging a few static meshes from the Infinity Blade pack into my level and starting to rotate one of them.
Alternate User Provided Repro:
A user reported that switching to wireframe view mode caused the crash.
Fatal error: [Link Removed] [Line: 176] Unreal Engine is exiting due to D3D device being lost. (Error: 0x887A0006 - 'HUNG')
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-40202 in the post.