We did this tour last year in June. The concierge at the Poly made the reservation; we were actually waitlisted for the day I wanted, and about 1 week before our trip they told me I was able to get the day I wanted. Believe I made the reservation about 6 weeks prior. I don't remember if I had a paper ticket or not; but the conductor who did the tour had a list with our names on it, when we met the tour.
Get to the TTC by 7am and ride the very first monorail to the MK. You may have to take a taxi from your hotel to the TTC. The transportation begins running 1 hour prior to the park opening; if you have to take a bus and a monorail you may not make it in time. When you get the the front of the MK just walk up to a CM at any gate and tell them you are on the train tour. You will have to show your park tickets & go through a turnstile. Our tour didn't begin until about 7:45 as the conductor waited for a few latecomers

Nice if you're the latecomer, but it pushed the schedule back. The tour did not finish until 10:45am.
The conductor who did our tour said the only place we couldn't take pictures was at the roundhouse; however the engineers who were there asked DS & I "Aren't you going to take any pictures?" So I took a few. But not of the roundhouse; only of the train. At the roundhouse, they back the train into the roundhouse, explain a few things, and then pull the train up a few feet and then you get out.
You get off the train at the Roundhouse, at the Toontown station; and then when the train gets back to Main Street there's a break (bottled water + cookies, I think) and the then the tour finished in the train station. Some people on the tour stayed after it was over to ask the conductor more questions.
We were told they gave away the spike souvenir prior to 9/11. Some people actually had them confiscated by the TSA, and then they started giving away pins. We also got name tags to keep. Here are some pictures: