New Atlas GP7 - How to install battery for 'RailSounds' ?

I don’t have the UP so my roof is a little different but I was able to remove the horns by lifting straight up on them.  Then I was able to remove the roof panel.  Everything was pretty tight though so it took some wiggling.

I've never owned an Atlas locomotive. But, doesn't the winterization hatch on the front end come off, then you could lift up the front end of the cover first and slide it forward, clearing the horns, then off? Or not.

On Lionel's 2006 Legacy GP7, it just lifts off, with a magnetized cover. In viewing your photos of this Atlas model, I'm amazed at the difference in Union Pacific's Harbor Mist Gray paint. Atlas got it right, very close to prototype. But Lionel through the years and even decades, has NEVER been able to get the right tone of this color on its Union Pacific diesels. Lionel's is always too dark. I wonder if it's too late to order an Atlas model? 😉

Anyway, good luck with installing the battery.

Doesn’t the last sentence in the instructions suggest that the body needs to be removed to install the battery?

Yes, the last sentence does suggest that the body needs to be removed - but it also says, "Refer to diagram on page 9."  If you check that diagram (you can see it in my post above; that's why I included both pages 8 and 9) it is of no use in this regard - but rather indicates where to add smoke fluid.

I think the documentation is a bit sketchy.  For example, it also indicates that a 9-volt battery is included with the locomotive - but I'm pretty sure it should indicate that such battery is NOT included.

Thanks, everyone, I'll get it sorted.

Fwiw, with all the trouble one has yo go through installing a battery on an Atlas O locomotive, uour better off instslling Gunrunner John's Your Last Battery [YLB] its a BCR for Railsounds. You install it once then forget about it!

Some of the Atlas locomotives are a bit of a PITA to access the batteries, so I'll second the suggestion of the YLB, once and done.

YLB - RailSounds Battery Replacement