This clip holds tighter to the Anki track and has a wide opening to easily guide the track into the clip. The clip is redesigned to hold the rails back further in order to give a little more track space and make it easier for vehicle to ride over the clip. The rails are a bit longer in order to have less space between them. I also added a straight rail.

Print three straight or outer rails per side of track. One inner rail per track. Two clips per rail is enough with the tighter clip hold. I've actually used four clips per three rails due to the rails being longer and clips holding tighter... thus the two inside clips can hold the edges of two rails.

Bonus: This tighter clip holds on to cardboard real good. The clip and rails can be used with a homemade cardboard track with other vehicles. Or, perhaps for other cardboard projects. The clip and rails also stand up on their own if you want to use them as a fence or something without being clipped to anything.

I printed on my Flashforge Creator Pro using layer height .3mm (fast). No supports needed if clip printed on its side. I used 25% infill and find that the clip holds tighter with infill.

Edit

Modified the clip to add a rounded top and add strength.