Where's the wagon? IN the background notes for 52, you interpret "AVOSOS HA'AGALAH - the ropes of the wagon (that bind it to a horse)" But Rashi interprets it as the rope the ties the cow to the PLOW.
When I went over the pirce, it read to me as an allusion to Chet Ha-EGEL, and an allusion to the maamar on amud bet that "labasof" the evil inclination becomes one's master (as if one were the hapless calf tied to the plow and forced to work). Kol Tuv
Rashi explains the words of the verse "v'cha'Avosos ha'Agalah" in Yeshayah 5:18 to mean "like the ropes of the wagon that are tied to the wagon in order to pull it [by way of tying the other end to an animal]," as we explained in the Background Notes.
Rashi in the Gemara here, when he explains that these ropes are used to tie the cow to the plow, does not mean to say that the word "Agalah" means "cow." Rather, he is saying that those ropes that are used for the wagon are also used to tie the cow to the plow. It is indeed a good question why Rashi does not simply explain here as he does in Yeshayah.
Regarding your suggestion, we do not find that the word "Agalah" (wagon) is interchangeable with the word "Eglah" (calf). (However, the source for the word "Agalah" may be because it is drawn by cows, "Eglos." Also, there might be support for your suggestion from Rashi in Bereishis (45:27), who says that by seeing the Agalos (wagons), Yakov Avinu was reminded of the Eglah Arufah.)
M. Kornfeld