Is a tri frame suitable for track racing?
I wouldn't. Track frames are purpose-built for racing at a velodrome.

Your tri frame will have a much lower bottom bracket. This can easily result in a pedal strike on the banked corners of the velodrome. Pedal strikes on corners with a fixed gear are bad; since the drivetrain is always turning, it will cause your rear wheel to jump perpendicular to the track surface. This will throw you into the bike on your left, and cause a spectacular crash.

Not as bad is that your frame has vertical dropouts instead of horizontal ones. Horizontal dropouts are made such that any loosening of your rear skewer bolts can only cause the wheel to move further into the dropouts. With vertical dropouts, any slip can potentially result in you losing your wheel.