I am aware that this video has been posted on the forum before, but this video really intrigued me, so as an up and coming journalist, I went ahead and did some additional research. Here are my findings:
Before you read, I would recommend watching the video. Despite being incredibly illegal, it is really cool.
The locomotive that was painted was UP 2519, an SD60M. This locomotive was in storage when it was vandalized, leading a consist with a bunch of other engines. The engines were all storage, as you can tell by the covers on their exhaust ports.
Some people questioned if this was allowed by Union Pacific because the engine was about to be scrapped. I can now confirm that this is not the case. I chatted with a representative from Union Pacific via Facebook messenger, and with their message I can prove this was an act of vandalism.
The locomotive has been repainted, much to the disappointment of many, in a coat of grey primer. It is on its way to the NRE shops where it will be repainted.
I don't know exactly where this happened, but am open to tips if anyone can supply. The incident occurred about a week ago. The suspects have not yet been found, but I will post updates here whenever I find more information.