The history and development of the US alco 244, its predecessors and the US 244 locomotive models.
Alco 60 tonner William Hunter CC BY 2.0
https://en.wikipedia.org/wiki/List_of_ALCO_diesel_locomotive_classes#/media/File:1926_AlcoGEIngersoll-Rand_Boxcab_Locomotive_11.jpg
Alco DL 109
(DVD) New York, New Haven & Hartford Railroad Volume 1 - A & R Productions
Note: the original publishers website (www.classicrailroadvideos.com) seems to be defunct.
NW3
Wikicommons Akampfer CC BY-SA 3.0
https://commons.wikimedia.org/wiki/Category:EMD_NW3_locomotives_of_the_Great_Northern_Railway_(US)#/media/File:Great_Northern_Engine_In_Whitefish.jpeg
FM sub apposed piston engine 1 Atlant CC by 2.5
https://upload.wikimedia.org/wikipedia/commons/a/a4/Opposed_piston_engine_1.jpg
NPR 190
NOYB#1 CC BY 2.0
https://commons.wikimedia.org/wiki/Category:ALCO_PA_locomotives_of_the_Nickel_Plate_Road#/media/File:NKP-_190_(49348063763).jpg
Museum of the American Railroad D&H alco pa shell.
https://www.historictrains.org/projects/alco-pa-1-image-gallery
DL109 video
(DVD) New York, New Haven & Hratforad Railraod Voulume 1: A & R Producions
Website defunct, avalible from 3rd party retailers.
Alco PA's in mexico
(DVD) Those-Incredible-Alcos-Volume 1 (diesel dinosaur delights): Pentrex
https://pentrex.com/DVD-Those-Incredible-Alcos-Volume-1-DVD_ALCO1-DVD
Green Mountain Rail Productions
https://www.youtube.com/watch?v=oes-MOuG8Qw&t=27s
Nelso Silva
https://commons.wikimedia.org/wiki/Category:Portuguese_locomotive_type_1520#/media/File:Somafel_1525_(39158630665).jpg