Doesn't matter what I break it with, empty hand, sword, arrow, the Better-Railroad's wrench, I get the vanilla cart back instead of the speedy

Minecraft 1.12.2
Forge 14.23.4.2705
Better Railroads 1.0.0
PairTree{Contents:"Partridge"}

I can confirm this, but as far as I can tell, the "speedy" cart doesn't actually travel any faster than the vanilla cart, at least on the "speedy" rails from this mod.

Correction: the speedy cart is indeed faster than the vanilla cart (either sent on its own or when ridden), as tested with nearly 1000 active powered iron rails in creative mode, but my first test in survival with a 707-block stretch of track, 5 powered rails to build up speed, and then powered rails about every 30 blocks did not show a significant difference in speed when riding.

Presumably, the faster cart riding on iron rails would require a different spacing of the powered rails to achieve and maintain top speed, but I haven't done any tests to figure out the optimum spacing.