Just the two questions!

Presumably the left hand route is the original one which was made unusable by the creation of the the reservoir?

The incline, I guess, would have been very early days - was this used in conjunction with the remainder of the FR route?

Photograph:

🔗Ffestiniog-Railway-User-Album-Image-004[linkphoto]Ffestiniog-Railway-User-Album-Image-004[/linkphoto][/link]

---

The inclines over the top are the original (1836-1842) route which were replaced by the Moelwyn Tunnel (1842) approached by the embankment on the left in that photograph. The tunnel was plugged as part of the CEGB's reservoir scheme, but somebody has excavated the entrance in the last week or so and the portal is now visible again.

Hmmm... I take it the tunnel itself wasn't flooded then?

---

Yes and no! The lake end was plugged, and the Portmadoc end was dammed to form a water supply. So, the inside is flooded, but not as a result of the power station. I believe the gradient is so steep that if you walk far enough the floor becomes dry.

Which end has been opened up? The dry or the wet? ;)

You'll probably have seen this, but some might not - here's a gallery with some pics of the building of the diversion: http://narrowperspectives.ukgeeks.co.uk/c1179998.html 

And some pics of the abandoned parts: http://disused-rlys.fotopic.net/c897405_1.html 

---

The cutting has been opened up at the wet end. I need to have a walk over to see what's been done.

I wonder why that has been done?

When I walked the old route when that photo was taken we walked from Tanygrisiau the "tide" was fairly low. By the time we had walked round to Brookes Quarry and back to Moelwyn Tunnel North the water was visibly getting higher. It was quite spectacular to see the water rushing across the 2 or 3 low points on the old FR embankment! It was going over the low points at a fair rate of knots!

There are several places where the railway deviates from the 1836 route if you know where to look. A lot of straightening work was carried out in the 1840's, and again when locomotives were introduced.

I have a very very poor photo of the old trackbed that was exposed by very low water conditions. Is this a regular occurance, or does it happen frequently?

Most days I think. Best is early to mid morning. Although one day last year I saw it very, very low mid afternoon.

Most days I think. Best is early to mid morning. Although one day last year I saw it very, very low mid afternoon.

It's pumped storage then?

No need for the deviation in that case, they could just have planned the FR timetable carefully... 😉

---

Yes i think it is, it empties during the day and fills up overnight, or vice versa. I don't know where the water comes from though!

There is a lake higher up the mountain (Stwlan Dam) which stores the water. When there's a high demand for electricity, the water is let out and goes through the turbines generating high value electricity for the grid and finaly ends up in the lower lake. This water is pumped back up to the higher lake using cheaper offpeak electricity.

Breakfast time, Lunch time, Tea time and the adverts on things like Coronation Street etc are peak demand times.

Dinorwig is a more modern bigger version.

---

Most days I think. Best is early to mid morning. Although one day last year I saw it very, very low mid afternoon.

It's pumped storage then?

No need for the deviation in that case, they could just have planned the FR timetable carefully... ;)

If you look how near the surface the old formation is, it makes you wonder if, with a bit more thought and planning, whether the original FR route needed to be flooded anyway!

I'm sure the dam could have been relocated a little further down the valley, or even another dam on the tunnel end of the lake with the stream carried over on an aqueduct, but I guess the CEGB wanted it their way. The power station itself is on the old formation. In a way, they did the railway a favour. The tunnel would have severely limited the size of any rolling stock, was unpleasant to work through in a train not to mention dangerous.

I'm always amazed that people think the pumped storage system is environmentally friendly. I was told by somebody that worked there, that for every 3 units of electricity they generate, 4 units from conventional power sources are used in order to pump the water back up to the upper reservoir. The station merely allows the grid to cope with surges in demand, as Manicminer says, the bottom reservoir often fills up around tea time, and is empty almost every morning before the world wakes up and turns their appliances on!

Oh, and did you know that Ffestiniog Power Station is the largets building in the World built from random-sized slate blocks?!

I'm always amazed that people think the pumped storage system is environmentally friendly. I was told by somebody that worked there, that for every 3 units of electricity they generate, 4 units from conventional power sources are used in order to pump the water back up to the upper reservoir. The station merely allows the grid to cope with surges in demand, as Manicminer says, the bottom reservoir often fills up around tea time, and is empty almost every morning before the world wakes up and turns their appliances on!

The 4 and 3 is certainly the figure for Dinorwig, I assume the same or similar applies for Ffestiniog Power Station.

In one sense it is environmentally friendly. If there wasn't Ffestiniog, Dinorwic, and the one in Scotland, several "conventional" power stations would have to be kept on permenant standby to cope with the sudden rises in demand. It also uses otherwise surplus energy to pump the water back up to Llyn Stwlan. When Dinorwic was opened they reckoned it saved CEGB (as it then was) £1M per week! Obviously Ffestiniog is much smaller, but the same principles apply.

Oh, and did you know that Ffestiniog Power Station is the largets building in the World built from random-sized slate blocks?!

Is that still the case? Or was it the case when it was built? An interesting fact either way!

I was interested to read that Cei Mawr on FR between Rhiw Goch and Tanybwlch is the the largest free-standing, dry-stone embankment in Europe!