A freely suspended pendulum has a period governed principally by its effective length, which is why regulation is done by raising or lowering the bob rather than by altering the train.
The train does not create the timekeeping. Weight or spring power passes through the wheels to the escapement, which releases the train one step per pendulum beat and returns a small impulse to keep the swing alive.
Escapement choice determines quality. A recoil escapement pushes the pendulum back slightly at each beat and tolerates rough work; the deadbeat escapement associated with Graham holds the escape wheel still during the pendulum's excursion and suits regulators.
Losses must be minimised, not merely compensated. Good suspension, a heavy bob, low arc and stable mounting all reduce the disturbance that impulse has to correct, which is why a regulator is bolted to masonry and a mantel clock is not.
Temperature matters because length matters. A steel rod lengthens as it warms and the clock loses; mercury jars, gridiron rods and later low-expansion alloys exist to hold effective length constant.