Any loco that appears in the shop is generally a standalone. Two exceptions that come to mind are Memories of Maerdy, an advanced loco with a small route that it can be used on that only comes with it, and some kind of route with a Class 119 loco. Everything else is standalone, and some also don't come with any scenarios, so depending on what you look for in your loco DLC be careful to read the description before buying. Some may also require other assets to appear properly, especially marketplace items.
A numerous amount of North American Locomotives that are standalone were later bundled in various routes, these include the following: -Union Pacific SD70 ACe & GP40-2 (Granger Heartland) -Union Pacific Challenger & Big Boy (Wasatch Grade) -Norfolk Southern GP40-2 (N-Line) -Amtrak F40PH (Soldier Summit) -Canadian National SD40-2W (Peace River) -Amtrak B32-8WH PHIII (Raton Pass) -CSX "Genset" & Metro-North P32AC-DM (Hudson Line) -NJT ALP-46 (North Jersey Coast & Morristown)
Wrong word. Cheyenne 1869 route included with https://store.steampowered.com/app/678005/Train_Simulator_Union_Pacific_No_119_Steam_Loco_AddOn/
There are other locos/trains that only come in Routes and can not be bought as a standalone Class 76 in the old Woodhead Class 76 + 506 in the BR Blue Woodhead Class 450 in the PDL and BML Class 377 in BML and CML Class 375 in CML and L2F Class 395 in L2F To name a few Peter