The problem with this type of robot is that it doesn't scale that well price-wise compared to a mobile type. You'll need longer rails on the sides and the gantr

The problem with this type of robot is that it doesn't scale that well price-wise compared to a mobile type. You'll need longer rails on the sides and the gantry will start sagging after a certain length. Meanwhile something on wheels or tracks has a slightly higher initial investment but has almost zero extra cost for driving a little bit further.