Poking around the Schleich website looking for livestock, I thought about buying their normal horse cart. However, detail photos showed it to be a bit clunky.
So back to square one, then I looked at their Medeval/Knight line. And found item number 42008, sold as an Ox Cart:http://www.amazon.com/Schleich-42008-Ox-Cart/dp/B000IOTV0I
I remembered seeing similar carts in this 1930s French Film (go about 1:10 in for the first):https://www.dailymotion.com/video/x83rzc_soigne-ton-gauche_shortfilms
It is an impressive and large model. Should look good on the railway with some straw this summer.
For the $15 I paid, VERY impressed.
FYI, Ridge Road Station have free shipping on Schelich orders over $40.