Well it seems Strayhorn submitted A Train to Ellington in December 1938 
according to one www site another site says 1941.
Give me a few minutes and I'll tell you the answer from another list I 
belong to - its a jazz list.

On Feb 24, 2005, at 12:43 PM, George Thompson wrote:

> I am abashed.  I should have thought that Billy Strayhorn wrote "Take
> the A Train" in 1941.
>
> GAT
>
> George A. Thompson
> Author of A Documentary History of "The African Theatre", Northwestern
> Univ. Pr., 1998, but nothing much lately.
>
> ----- Original Message -----
> From: [log in to unmask]
> Date: Tuesday, February 22, 2005 10:28 am
> Subject: Underground Sidewalks of New York
>
>> In a message dated 2/22/05 10:13:40 AM Eastern Standard Time,
>> [log in to unmask] writes:
>>
>>> I don't think that the subway lines got alphabetic designations
>> until
>>> well after WWII.
>>
>> George, you're kiddin' me!   You still reading those darned 19th
>> century
>> newspapers?  Hey when you get up to 1932, when the IND opened, you
>> will find the
>> first letter designations, beginning with the first letter of the
>> alphabet,
>> associated with the IND.  Hence, the "A" train, the major express
>> route on the
>> line.
>>
>> sign me, your admirer,   Christopher Gray aka Billy Strayhorn
>>
>
>
Jazz is freedom. - T. Monk