Tridents used a vertically and a transversely mounted engine.
How? Vertical means that the engine is in an upright position.
Transverse means that the engine is mounted perpendicular to the
chassis.
The Javelin chassis is no longer in production. There are some
operators in Malaysia, such as Triton, which use the Dennis
Javelin. Be forewarned that not all buses badged as Dennis are
really Dennis. I've seen a number of 'fake' Dennis buses.