Fells skyline loop - vertical gain?

I was on my bread-and-butter afternoon trail run on the skyline loop in the Middlesex Fells today when I wondered, how much climbing is there? It tops out at 317' on Bear Hill (including that as an add-on), yet a good amount of time is spent climbing and descending the many bumps (fells) along the way.

I counted contour lines on the Friends of the Fells map and came up with 432m / 1417ft, but there was a fair bit of splitting the difference with in-between-countour-line troughs and bumps. With the Bear Hill add-on, the distance is probably just about 7 mi and the vertical might be 1450 ft.

Has anyone ever tried to measure the vertical gain with GPS, or seen a figure somewhere?

Here's what I found by Googling Middlesex Fells Skyline, though it does increase the length to 8 miles:

aHaB - Middlesex Fells Skyline Trail The 8 mile Middlesex Fells Skyline Trail has gross elevation gain of 1500 ft. The half mile side trip to Bear Hill increases the gain to 1600 ft. ...
www.geocities.com/yosemite/trails/1171/MSFSky.htm - Cached - Similar

Interesting graph, thanks for turning that up. The comparison of Blue Hills vs. Fells does capture graphically what you experience on the trails. Not clear how he calulated vert? The 8-mile distance seems odd, AMC says 6.8 and Friends of the Fells say 6.9 - though I suppose that I should be pleased by the possibility that I have been going farther and higher than I thought...

Mohamed says 7.0mi, 1000'. On a trip like the Fells, where the elevation change really is rather small, I would guess GPS measurements of elevation and distance to both run a little high.

The 3m contours on the friends map are from the USGS quad - so I think that the real gain ought to be something close to the 1450' I got from those contour lines. The vertical GPS errors would make it difficult to distinguish real bumps from imaginary (error) ones, so it may never be as accurate as using 3m contours. I suppose looking at GPS profiles of hikes with more sustained climbs you would be quicker to ignore the noise.

String method on the friends map gets close to 6.8 mi.