The subject of moving a Bridgeport comes up often. Here are pics I saved from one user's website
just in case the site disappeared.  Glad I did, because the site is gone!

1)   BP on trailer.

2)   Using come-alongs pulling at the base, literally drag the mill toward the ramp.  When you get
     to the ramp, control the uphill side (both top and base) with straps, and slowly inch it down.

3,4) Still inching down the ramp, It's a matter of pulling it inch by inch, while paying out strapping
     on the uphill side.  Note the blocking under the ramps, you want to ensure the ramp(s) dont collapse.

5)   Nearly at the bottom now, you have several choices before front edge touches down, such as pipes
     and rollers, pallet jack, dolly, etc

6,7) Just ease 'er down.  Note the number of floor jack used during the entire process.

The pics show this user utilizing a very heavy duty pallet bolted to the base, giving it large stable base
during the process. I've seen pics on the web (cant find them now) where bridgeports are moved on a flatbed
type tow truck.  The flatbed tilts and slides to ground level, then the mill is slid down to ground level,
controlled by the winch and strapping to the top side, just like the pics above.  No pallet used, just the
BP base sliding directly on the aluminum diamond plate ramp.