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Merthyr Marathon MM5 - Terrific Trevithick

A cache by Write and Mane Send Message to Owner Message this owner
Hidden : 9/28/2003
3 out of 5
3 out of 5

Size: Size: regular (regular)

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Geocache Description:

The fifth in a series of caches aimed at exploring Merthyr Tydfil and, perhaps, most deserving of the "marathon" qualification! You will need information gained in completing an earlier cache in the series in order to start this one. There are ten stages: the first nine are virtual caches, the last a medium sized plastic container. This multicache is designed to provide a circular walk of about 6½ miles with a total ascent of about 500ft (the sting in the tail!) and would take half a day.

We met Richard Trevithick's locomotive in MM2 and this cache was placed shortly before the bicentenary of its pioneering first journey on 21st February 2004, so we have to explore more of the Penydarren Tramroad. Trevithick's work was sponsored and encouraged by Samual Homfray, owner of the Penydarren Ironworks. Homfray had bet 500 guineas on the success of the venture with Richard Crawshay of Cyfartha and the stakes were lodged with Richard Hill, Ironmaster at the Plymouth Works. Despite the acknowledged success of the engine, it is remarkable that the railway age did not take off for another 20 years. Since the cache was placed, information boards, sculptures, innovative seats and, even, a tea shop have appeared along the Taff Trail and a nature reserve has been designated. Some cosmetic improvements in the interests of cyclists have slightly obscured the tramroad remains, making the answering of the question at VC6 slightly more challenging!
The whole of this multistage cache lies within about a mile of the given location, but this does not represent a practical starting point! As an alternative to walking, cycling would be a feasible option. By driving between the first two caches, the circular walk can be reduced to 5 miles. Even maximising the use of a car, you should expect to cover about 3 miles on foot. Most of the virtual caches are on the route of the tramroad (now followed by the Taff Trail) through a picturesque part of the Taff Valley. The final ascent reaches a distinctive landmark and viewpoint.
The letter/number codes used in previous caches in the series do not apply here.
Virtual Cache 1 N51 ab.cad W003 ef.ggb
If the day of December when the Prince of Wales planted the laburnum tree at Dowlais Stables was x and y =x divided by 2, efggb = xxy multiplied by 88 and abcad = (efggb multiplied by 2) less 160.
It is appropriate to start with a replica section of tramroad track. Note the single spike fixing that would have held the ends of adjacent rails in place. Originally, the spikes would have been driven into oak plugs inserted into holes drilled into the stone "chairs". But before we move on, we need to check a few numbers on the nearby information board – on the bet winning journey, hj tons of coal and kj men covered the distance in m hours n minutes, at an average speed of p.q km/hr.
Virtual Cache 2 N51 af.djj W003 eb.npd
The tramroad was a commercial enterprise. This house indicates how charges for use would have been levied. What House is this? The number of letters in the answer is s.
Virtual Cache 3 N51 af.drm W003 ef.jjh
where r = q – k.
The tramroad crosses the River Taff twice: the original bridges were wooden but, following the dramatic collapse of one in 1815 under the weight of a train of trams, they were both replaced with the elliptical-arched stone structures we can see today.
Virtual Cache 4 N51 af.nqj W003 ef.hsg
The double viaduct carries the Taff Vale Railway over the river and tramroad. The first (downstream) side, designed by Brunel, was completed in 1841, the second in 1864. But the railway was instrumental in the decline of the tramroad, which finally closed about 1880.
Virtual Cache 5 N51 W003 ef.drh
Railways competed hard for the coal transport business. Here the dramatic Great Western and Rhymney Valley Joint Railway crossed the valley and disappeared into a 703 yard long tunnel through to the Cynon Valley. Just a hundred yards further north, a second crossing by the same railway continued up the opposite side of the Taff Valley. As a result of mining subsidence, both of these viaducts had been shored up by huge timbers by the time that the railway closed and were blown up for safety reasons. Cyclists are warned that the surface of the track deteriorates around here. This is because this part of the tramroad is a scheduled ancient monument, as you will see from the increasing numbers of the original stone "chairs" in evidence.
Virtual Cache 6 N51 af.sqd W003 ef.dkp
The pattern of stone "chairs" does something strange here.
What sort of place on the tramroad was this? The number of letters in the answer is t.
Virtual Cache 7 N51 mj.rdq W003 ef.spq
The last remaining bridge over the tramroad removed a level crossing and, as a bonus, a dog-leg above a precipitous drop into the River Taff. Since we leave the tramroad here, it is worth reflecting that Trevithick never gained the recognition he deserved and died penniless in 1833, aged about 52.
u = number of arches in the only bridge over the tramroad.
Virtual Cache 8 N51 mj.htj W003 ef.ssr
Pont-y-Gwaith (the bridge of the works) may refer to an ironworks which was destroyed by Cromwell's cavalry in 1648. The stone arched bridge was built by William Edwards, who is more famous for the old bridge across the River Taff at Pontypridd.
v = (date Pont-y-Gwaith repaired) - (date Pont-y-Gwaith built in stone) - 177
Virtual Cache 9 N51 mj.unr W003 uq.qdr
We cross the line of the Glamorganshire Canal. Toll charges on the canal, owned by Richard Crawshay, had provided the financial incentive to the owners of the Penydarren, Plymouth and Dowlais Ironworks to build the Penydarren Tramroad. While not immediately obvious, the canal still carries much water here - the trunk main carrying water from the Brecon Beacons to Cardiff is laid on the line of the canal.
Regular Cache 10 N51 pq.vds W003 rj.jdr
Hopefully, the views in all directions are adequate compensation for the climb to the dramatic notch that has been visible on the skyline for part of the trail. Formed by quarrying (stone for some of the bridges and viaducts which we have passed on route), this feature has a number of local names, but we prefer the "Giant's Bite". For those on foot or bike, there is advice inside the front cover of the cache log book to help you back to your starting point. BECAUSE THIS IS A POPULAR LOCATION AND THE CACHE HAS GONE MISSING TWICE, IT IS WELL HIDDEN. PLEASE ENSURE THAT YOU LEAVE IT THE SAME WAY AND THAT THE ARRANGEMENTS ARE SECURE IN THIS SLOPING LOCATION. THANK YOU.

Additional Hints (Decrypt)

Jryy onpx haqre n ovt ebpx, whfg orybj gur znva cngu nebhaq 'gur onpx' gb gur Ovgr.

Decryption Key


(letter above equals below, and vice versa)



  • View of Giant's BiteThe Bite is the small notch in the skyline. This view can be seen on the final stage of the cache.
  • View through Giant's BiteThis rather hazy view looking down into the Taff Valley is taken close to the high point of the cache. The viaduct at Virtual Cache 4 can just be seen in the bottom of the valley.

59 Logged Visits

Found it 47     Didn't find it 1     Write note 4     Temporarily Disable Listing 3     Enable Listing 3     Owner Maintenance 1     

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Coordinates are in the WGS84 datum

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