track geometry will also have a less sloping head tube and the forks will have 0 rake to them. it makes the bike very twitchy on the road, but this responsiveness is neccessary to shoot up the walls and manuever, etc. track bikes will typically have very short stays. the bottom bracket is higher as well for clearance issues.

edit: that sloping toptube you are referring to may be a pursuit bike. those will usually run a small fork with a 650c front wheel.