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Saturday 4th August 2012 saw Peter and I joined by Dougie Clark and his girlfriend Elaine to tackle the Tyndrum Hills of Beinn Dubhchraig and Ben Oss.
The weather was surprisingly pleasant to begin with but later on a big shower came in from the north giving us an hour of drenching.
We parked the car at the usual carpark for this route, Dalrigh just off the A82 before Tyndrum coming from Crianlarich. The walk in is along a tarmac road crossing a river and then another bridge over the railway line.
The Walkhighlands website official route doesn't emphasise enough that you should *immediately* leave the main path after this railway bridge and begin the bogfest!! We made the fortunate error of starting on the landrover track, and heading for the second rickey bridge. This avoids the walk through the beautiful pine forest which is the boggiest walk ever. If you want to folflow the official route turn sharp right and virtually folow the railway line until you reach the extremely rickety bridge over the main river. This is made from some old rails with planks across, a lot of which are missing. After that you follow the bogfest all the way through the Scotts Pine forest.
View of River Cononish from first bridge:

Looking back down the main path to Beinn Dorian:

The 2nd rickety bridge:

Peter, Dougie & Elaine with Ben Challum behind:

We stayed to the left of the gorge and both paths merge at the top of the main gorge, whence we crossed the river and followed the patch all the way alongside the stream and up to the beallach. From here you swing left to catch the first munro of the day, Beinn Dubhchriag 3209 feet. The views down Loch Lomond are stupendous!
Loch Lomond from almost Beinn Dubhchraig summit:

At this point the rain struck, so it was on with the waterproofs and a descent of around 1000 feet to the beallach between the two munros.
The rain moved in from the North:

Interesting rainbow effect in front of Ben Challum:

Here we made our second fortunate navigational error of the day (walk report stowed in backpack away from rain!). We missed the initial track up and followed the stalkers path round the front of Ben Oss. When we reached the high up Lochan we spotted a direct route up to the summit which would be a magnificent scramble with no exposure or danger. This was the highlight of the day, especially for Elaine as she reached the ridge first! From there a short walk to the summit of Ben Oss with it's excellent views of the MIGHTY Ben Lui.
The MIGHTY Ben Lui from Ben Oss:

Dougie and Elaine raise the flag to celebrate the Olympics:

Beinn Dubhchraig from Ben Oss with Ben More & Stobinian in the distance:

From here you either decide hat you are tackling Ben Lui or you retrace your steps. We'd done Lui before anyway and time was marching on - this walk alone took us 10.5 hours!
Rain cleared and view down to Loch Lomond and Arrochar Alps:

Beinn Dubhchraig reflection:

We then headed back down the normal route but diverted around a bit of ascent down to the left, heading back to that high lochan. Then the easy ascent to the ridge of Beinn Dubchraig and drop down across the moorland to the gorge. This time following the main path - did I mention it's boggy! - into the pine forest and emerging back at the railway bridge.
The midges were well and truely out and we managed to get back to the car just before dark - this is one LONG walk!
Short video of the walk:
http://youtu.be/7RABQx3tuFY?hd=1