not sure of the syntax but id say you'd want a variable that increments by say power of 2 to get the speed to go up. e.g 0= stationary 100= fast moving,

1 x2 =2
2 x 2 =4
4 x 2 =8
8 x 2 =16 etc...

so like x *=2


and then maybe get it to follow a path, as to a template im not sure really, sorry i cant be more specific, im new to coding in 3DGS