The friction between the large diameter roller (marked with ○) and the small diameter roller (marked with ●)
Both rotate at the same time, and the speed of the conveyed goods is determined by the ratio of the roller diameters.
This is 2.5 times the chain speed.

When the chain runs at speed ν, the outer circumference of the small diameter roller
The peripheral speed of (the rolling speed of the rail running surface) is ν.
At this time, the large diameter roller and the small diameter roller rotate at the same angular velocity,
The peripheral speed of the large diameter roller is calculated from the radius ratio (R/r) × ν.

Therefore, the speed V of the transported object is the peripheral speed (R/r) × ν.
This is the combined chain speed ν.

V=(R/r)×ν+ν

V=(R/r+1)×ν

Here, the ratio of radii (R/r) is ≒ 1.5,

V≒(1.5+1)

ν≒2.5ν