The Jigglin George is a solid, yet relative inexpensive super "Railroad Simulator" !!
http://www.ebay.com/itm/Rising-Son-JIGGLIN-GEORGE-Exercise-Machine-MR-910SA-5-Speed-With-Timer-/182008278594?hash=item2a6089ee42:g:SQYAAOSwUV9Wn~es
http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Dhpc&field-keywords=Jigglin+George
I bought one new a few years back and have used it extensively.
To almost simulate a railroad enema on a caboose try this at home. And come right back here to validate your RR Simulator Test. OK??
Here are your pre-trip orders:
Establish working dry run experience with a Jigglin George.
Get your needy arse its well deserved enema ready and set up close to your RR Caboose Simulator.
Grease and fit your treatment delivery stem into your colon's vent. Send in a cup of air straight away, removing the stem to prevent air leakage from the experiment zone.
Fit the delivery stem onto your enema kit. Grease it some more if needed, and I know you do, OK?
Work it back inside your little gas pocket with a twisting motion, being careful not to loose any air.
Get situated onto your Gigglin George machine, while being careful not to loose track of your Stem's placement.
Start taking on your water infusion, and start running the Simulator. When your load starts sloshing sufficiently, you may turn off the water injector and begin enjoying the ride. A trip like this can easily last 20 minutes. You are required to take notes to properly document the RR Simulator Test. Please report any leaks or mishaps in the trip. But especially please note the sounds and sensations incidental to the experience, with a new view to all the possibilities for the rest of us to consider.