Trans Siberian Railway Safety

Hey everyone!

I'm planning a trip on the Trans Siberian Railway in August Protected content to Beijing) and I'm wondering about the security of the train. I'm not super worried about pickpockets or anything like that BUT I am a bit worried about terrorism. With Isis threatening Russia, I can't help but think the TSR might be a target, which is making me hesitant of making the journey. I'm wondering what the security is like, are there metal detectors you must go through before boarding the train? Is there a police presence on board? Everything I've read about the TSR is that it IS very safe, but I feel like the articles are more talking about being pickpocketed or kidnapped or something, but nothing in regards to a bombing or serious terrorist threat. Any information would be super helpful! And if anyone has an opinion on whether or not I should be traveling in Russia at all because of the Isis threats I'd be interested to hear it. Thanks!! Safe traveling :)