Question about Boston & Albany tenders

Okay, I have a question about what tenders went with what locomotives on the B&A... I guess that this question is also generic, but is a locomotive "married" to a certain tender, or will the tenders be switched around at random? Ultimately, I want to know if the six axle tender seen behind this Berk would have been a usual site on the B&A:

Image: http://abpr.railfan.net/abprphoto.cgi?/ ... xa1406.jpg


Of all of the photos of B&A Berks on SteamLocomotive.com, this is the only one I see with this specific type of tender... The vast majority of the Berks have a four axle tender like this:

Image: http://www.steamlocomotive.com/berkshire/ba1409.jpg


On the other hand, it seems like that first six axle tender is more often found with B&A Hudsons, like this one:

Image: http://abpr.railfan.net/abprphoto.cgi?/ ... bxa613.jpg


But, a couple of the photos show the Hudsons with the smaller four axle tender that most Berks are seen with:

Image: http://abpr.railfan.net/abprphoto.cgi?/ ... bxa614.jpg


So, which of the above is the proper tender for the Berk and then for the Hudson? If the six axle tender was indeed a Hudson style tender, then why was it being used on a Berkshire?

Here's a four-axle tender on Berkshire 1405 from my collection.

Tenders were not married to their locomotives. It seems to be common for tenders to be switched but I don't know the reason. One reason for the "upgrading" from 4-wheel truck to 6-wheel truck tenders was the equipping of J3 Hudsons and some J1 Hudsons with PT centipede tenders in the 1940s. The old 6-wheel tenders got passed down to B&A J2 Hudsons and apparently to some Berkshires.
All 50 J-3's were equipped with PT tenders at some time.
Most PT tenders were used by more than one locomotive.
65 PT's were built for use on Hudsons.
Six Hudsons had three different PT's assigned.

From builder photos and NYC locomotive diagrams it would appear that:
A-1a (1400-1424) & A-1b (1425-1444) Berkshires were built with 4-wheel truck tenders
All J-2 Hudsons (600-619) were built with 4-wheel truck tenders.

From photos that I have seen it would appear that most of the J-2 Hudsons and at least a few of the A-1a,b Berkshires received 6-wheel truck tenders.

All of the pictures of A-1c (1445-1454) Berkshires I have seen had 6-wheel truck tenders. These were NOT hand-me-down Hudson tenders with the rounded coal bunkers, but had straight sides.

Thanks for all of that information Dave!