Great Western Coffee Shop

Just a little tip for those that are sat on a train and might like to know - I'm sure several members of the forum know about this already, but maybe not everyone? Apologies if the explanation is a little basic, but I'm assuming that a regular punter might be reading.

All main lines have mileposts every 1/4 of a mile, which enables all sorts of people, including drivers, to know their location and the location of various things such as temporary speed restrictions etc. They are normally yellow posts which appear on the left-hand side of the track as you look towards London (known as the 'up' direction). There are a couple of exceptions to this as between Southall and Reading, and between Reading and Basingstoke new blue diamonds signs indicate the mileage - expect them to become more widespread as the years go by. The number on them usually refers to the mileage from London, though there are lots of exceptions especially in more rural areas.

There's a picture of a typical one here: http://en.wikipedia.org/wiki/Image:Railmileposts.jpg (http://en.wikipedia.org/wiki/Image:Railmileposts.jpg)

To find out the speed of your train, use a stopwatch to time how long it takes to travel the distance between two mileposts, i.e 1/4 of a mile. Train speed is 900 / time in seconds for 1/4 of a mile. Obviously if you have timed 1/2 a mile then it's 1800 / time. Because of their location, it's usually easier to spot them when travelling in the 'down' direction from London.

If you're going 90 mph it will take 10 seconds to travel 1/4 mile. At 125mph it will take 7.2 seconds. There's a full breakdown here: http://www.bevanprice.freeuk.com/timing3.htm (http://www.bevanprice.freeuk.com/timing3.htm)

For the more technically advanced, if you have a portable GPS receiver - some mobiles now have them as standard, that might well display your speed too, though I am not sure how reliable they are?

Couple of points - if you want to be accurate then time it over a mile - so 40 sec = 90mph, 36sec = 100mph etc.

The blue diamonds are very prone to graffiti - I've never seen graffiti on a milepost. Funnily enough, that's true of the current road style speed restriction signs, whereas the yellow stencilled ones don't seem to have the same appeal for graffiti vandals (I refuse to call them artists).  SO I hope the blue diamonds don't become more widespread.   

if you have an iphone there is a whats my speed application which is quite cool, its also interesting using google maps to see where you are

I tend to sit in the back cab and watch the speedo. ;D

As a rule of thumb...and apologies to the many savants on these pages...

158 units max at 90 mph and all other sprinters/pacers at 75mph.  Connect any another type of sprinter, or heaven forfend... a pacer, to a 158 and max permitted speed drops to 75 mph.

The above is without regard to line speeds, but Gloucester to BPW sees 90 mph 158 running.  Max line speeds on the Westbury line are lower.  On the Severn Beach line units rarely get to above 45 mph.

HST's can run at 125 mph where line speeds permit, although they are probably capable of at least 150mph without restriction.  The type was renowned as the world's fastest diesel train for years, although I believe that the Russian TEP 80 locomotive has now been tested at 150 mph plus.

Think you will find that when originally  introduced the HST was designed to run at 148 mph, but was later restricted to 125 i think i read somewhere that certain drivers were passed to drive at thhe faster top speed

It was able to run up to 140mph+, but a limiter was put in because of persistent overspeeding. Like most vehicles, including all cars, it's maximum speed is faster than it's design maximum.

An HST set holds/held the record for the World's  Fastest Diesel Train.  Established way back in the late 70's somewhere in Yorkshire I think.  148 or poss 149 mph.  Sounds impressive, but small  beer compared to the TGV and ICE trains on the continent.  Even RENFE in Spain have their own TGV or more properly AVE trains and are busy building new lines for even higher speeds.  Wake up England!

ICE is fairly slow actually, most of their "high speed lines" are much slower than the CTRL.

But in the UK, our cities/ population splurges are much closer together, so it is not really worth it as you either speed past many cities (loosing trade), or stop too often (loosing speed). Exceptions obviously are lines like London to Birmingham.

I think that more quadruple tracking and raises of line speeds to 140 and 155 mph, should be satisfactory for the UK, and the best value for money.

Is it worth building a 200 mph High Speed Line from London to Oxford, when much of the route could take 140, maybe 150 mph? You would spend billions more, and only save 15 mins at most.

Well, for many years, it's been a rather useful trick to be able to work out the speed of your train - from sometimes the most unlikely situations (link below.)
http://barzilai.org/cr/sherlock.html

 ;) :D ;D

On its own, no, of course not, but as a branch off any future London-Birmingham and the North HSL, which would be likely to run somewhere along the Chiltern Line/Great Central and M40 corridor, so as to serve Heathrow airport, then it would make perfect sense. Greengauge 21 (backers of an HSL) suggest a 30-minute timing to London, which would be more like a 25-minute saving on current FGW 'express' timings from Oxford.

Even with Reading rebuilt, I can't see the days of 45-minute Oxford-Paddington HST runs coming back, simply because of the number of trains now running between London and Didcot - and that won't change, whatever the top speed is. But if Oxford services were to go via an HSL, then that would free capacity on the GW Main Line for more, faster trains to Bristol and South Wales on the existing route

Had my GPS on the 17:33 HST down from Exeter, a lethargic 5mph following the 17:17 Paignton Pacer till we came to a complete stop outside Dawlish  - the weather was fabulous and the view delightful.
30mph was seen around Teignmouth and 50mph up to Newton Abbot - after that depression set in - 50 odd was all we did down to St Erth where the St Ives branch had already left without us.
We were about 20 minutes late, passenger flow was low, stops inordinately long, no attempt to catch up time, no apology.
I've been on delayed services that have arrived early so it's possible to catch up.
Also ( because I don't know too much)...I usually travel on HSTs once a week but am on hols ATM - why all the concertinering every day - like riding on a jelly...from start up, on the flat, up gradients...is this a traction issue or driver training ?
  
  

ICE 1 and 2...top design speed 174 mph.  ICE 3 Top design speed 205mph, but in fairness, as you point out, it is so often the line, not the traction which dictates maximum service speed.

As such, HS2 to the north would possibly be viable, first stop Birmingham.  As discussed elsewhere, the nature of the GWML precludes a TGV style LGV, but higher line speeds, associated cab signalling and a workable scheme to electrify into South Wales are not only desirable but IMO, vital.

concertinering???........This is caused by bad railhead conditions / wheelslip...its the autumn now leaves on the line etc

The diameter of the wheels and the maximum safe RPM of the traction motors being the limiting factor. Obviously the smaller the diameter as the wheels wear / are turned to correct worn profile the faster the wheels and motors will turn for a given speed. Also factor in an allowance of about 10% to ensure a safety margin even when the bogies are getting near their overhaul time.

The HST's were designed as a 125 mph train, at the time of designing them (early 1970's) track geometry and signaling would not allow an higher speed, HST's had to be able to stop within the constrains of the standard signal distance.  The other consideration was the size of the power unit to attain that extra 25 mph a much larger engines and alternators would have been required, the extra 25 mph not being seen in the 1970's as adding any extra marketing value remember they were advertised as trains that went 25% faster.

When I was an apprentice we would go out on ex works test runs on the new trains 4 coach's and 2 power cars with the boffins from Derby RTC tinkering we could go along the stretch between Didcot and Swindon in excess of 130 at certain times doing emergency brake test at that speed was exhilarating and if you were not sat down frightening.