I think I found my answer

[NW Modeling List]

Sorry, but not quite. In the modern steam era, N&W did not put the actual locomotive numbers on the tender, but each tender did have its own number, frequently, but not in every case, tenders stayed with their original locomotive most of its life, unless it was changed by putting larger tanks on. 

I cannot accurately say if the system of number the tanks separately was in place on the early days, but since the question was regarding the Y6b construction beginning in 1948, it was in place at that time. There are lists of tender numbers as assigned from the early 1950s.

The number for tenders was first two or in the case of really tiny tenders, one, was the capacity in gallons of water, so a 22XXX was a 22 thousand gallon tender. The next numbers, usually three digits, was the actual tender number. 

For example 611's tender number is 220165, which stayed with her through all her service. Now, with added coal boards, she can carry more than the original 35 tons of coal, but since I've never heard a good calculation on how much more. In interest of historical accuracy, I stenciled the 35 tons on the back of the tank when she was repainted in 2015.

Ken Miller
On Oct 1, 2016, at 3:37 PM, NW Modeling List wrote:

> N&W did not number the tenders as when the engine went in for servicing they could get a different tender.
> The data on the rear was water capacity in gallons and the coal capacity
> below the headlight if you checked the links.
> 
> -Lynn-
> On 9/28/2016 1:37 AM, nw-modeling-list-request at nwhs.org wrote:
>> Date: Mon, 26 Sep 2016 22:50:51 -0500
>> From: NW Modeling List <nw-modeling-list at nwhs.org>
>> To: <nw-modeling-list at nwhs.org>
>> Subject: I think I found my answer
>> Message-ID: <mailman.585.1474972950.18152.nw-modeling-list at nwhs.org>
>> Content-Type: text/plain; charset="us-ascii"
>> 
>> I believe I found my answer about the lettering on the rear of the Y6b
>> tender.  While I didn't find a legible photograph, I did found the data for
>> the tender in my N. & W. book by Richard Prince.  So I am back in the game.
>> 
>> 
>> 
>> Mark
> 
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