Back Of Envelope Cds Deciphering Question

Hello all,

Bit of a postal history question. Photos show front and back of postal stationery from 1905. Don't know what you call the cancel on the back, but ((in my mind)) it shows the envelope arriving "somewhere" and it gets stamped or cancelled again.
Anyway, looking at the back, can you help me decipher what it means? The letter was mailed from Tyler, TX to Kansas City, MO.
Your help, as always, is appreciated!
Dave

The Double CDS in the top image is a Railroad receiving mark. It read as follows:

REC'D "Received"
K.C.MO "Kansas City, Missouri"
VIA "By way of"
K.C. 7 CALDWELL "Kansas City & Caldwell railroad"
TR. 4. "Train 4"

The postmark on the front is from a Doremus machine cancel, located at the Tyler Texas post office

Wow, thanks! As I look at it now it makes sense (and makes me think I could have figured it out) but I certainly do appreciate the quick response and the excellent information!