Old Crawler Tractor vs. Crawler Tractor

[Proteus]

According to the description, the old crawler increases harvesting speed and the newer one allows you to uproot vineyards.

But does a more modern crawler also allow you to speed up harvest? (meaning the Old Crawler Tractor can be sold after purchase of a more modern one)

One would assume that a more modern version of a vehicle can do the same things as the old version (in addition to the added capabilities that come due to its modernity)

Similar question with regards to the Cab Tractor vs. the Old Tractor

[Ando]

I don't think so. The way I understood it, each tractor actually unlocks a new upgrade which doesn't affect what you unlocked before, with the exception of the very last tractor which speeds up the harvest even more than the old tractor, if I remember correctly (afk).

[ulzgoroth]

As you should know from the descriptions, the cab tractor speeds up harvesting, and doesn't say anything about trimming. It does totally supersede the old crawler tractor.

However, from observations it may actually be the case that the cab tractor can also be used for trimming. It's not easy to tell what's happening since fieldwork cards don't really indicate which equipment they're using.

It's possible that the crawler tractor can also help with a harvest like the old crawler tractor. I didn't bother to get it until I already had cab tractors so I've never checked.

[Proteus]

Now that I have enough money to afford both typesI just checked up both.

The answer is mixed:
1. Yes, a Cabin Tractor can be used for Trimming (just like the Old Tractor)
2. No, the Crawler Tractor doesn't seem to help with Harvest (unlike the Old Crawler Tractor)

So, it seems as soon as you have accessto the Cabin Tractor (and the (modern) Crawler Tractor) you only need 2 Tractors anymore:
1. Crawler Tractor (for Uprooting)
2. Cab Tractor (for Harvest and Trimming)