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I was driving along the a30 lastnight when I noticed a train Exeter bound and was struggling to keep up at legal speeds? Was between Exeter and honiton

More than 70mph then wasn't it  :P

yeh but seriously anyone know

According to Network Rail, 80 to 105 mph.

See figure 4 on page 8, at http://www.networkrail.co.uk/browse%20documents/StrategicBusinessPlan/RoutePlans/2008/Route%204%20-%20Wessex%20Routes.pdf

So yes, rather faster than Citylink, relex109!  ;)

thats quite a high speed for that line isnt it! i mean the distance between honiton and feniton is nothing so why 90?

90 is the highest speed of the 158s.

Why run any slower? Do you want extended journey times? (and that route is slow enough!)

well its a class 159  :P and yes 90 is the highest speed of these units but i didnt think the speed of the LINE was 80-105 for a single line in that area that quite impressive! the line between weymouth and  c c is only 40-80

The line between Salisbury and Exeter has a general limit of 85mph with few restrictions (90mph Salisbury-Worting Junction and 100mph onto London). This is largely because it was built as a main line to rival the Paddington route, so it's fairly straight and none of the gradients are steeper than 1 in 80. The Weymouth - Castle Cary route was also built as a main line (Weymouth-Westbury-Swindon-Paddington) and so that's also fairly straight. That's presumably maintained to a lower standard as the general limit between Dorchester and Castle Cary is 75mph, although it's 40mph between Yeovil Pen Mill and Yetminster, while there's a 15mph through the passing loops at Dorchester, Maiden Newton and Yeovil.

I don't work for the railways BTW - I just like to know how fast I'm going as a passenger!

Very interesting, thanks.

I, too, like to know speed limits on routes I travel on.

Do SWT reach 100 mph much around London? Those Waterloo lines are quite congested are they not?

In the lead up to electrification of the SW Main Line back in the mid 60s, the Bullied Pacifics, particularly the Merchant Navys regularly achieved 100mph plus between west of London and Southampton.  The high HP electric REP/TC combos were timed at 100mph as were the Wessex Express trains which superseded them.  Things are less breathtaking on the West of England line after leaving Basingstoke, but the 159s, (a modification of the 158 with a slightly different braking system, which means that these units will not run in multiple with other 'sprinter' types), easily cope with the 90mph max line speeds.

they can run in multiple with other sprinters,i remember a case last year when an fgw 158 en route back from ports had problems so fgw hired a 159 to couple up and box the defective cab in to get back to bristol.also in wessex days a 159 coupled to a stranded 153 at warminster to get it in to the bay at salisbury to get looked at by fitters.

I think the fast lines in the middle are 100mph from Worting Junction to Wimbledon with 90mph on the outer slow lines. I'd assume that the electric Desiros on fast Bournemouth services can still reach and maintain 100mph without difficulty. The Surbiton/Wimbledon area is where things start to get really busy. I don't often travel in that area though, so I could be wrong.

Welcome to the forum The Grecian

Thanks. It would be interesting to look at 1960s timetables from places like Woking and Surbiton into Waterloo, and see whether the journey times are longer today. I assume that there are many more (peak) services now.

The third rail in London is nominally at 660V this is to make it compatible with LUL, where as out side the London area it is nominally 750V.

There are plans to raise the London area nominal conductor rail voltage to 750V this mainly to improve power supply capacity, not to increase train speed, without adding as many substation if the voltage were to remain at 660V, there has to be some interfacing and separation between LU and NR, all of which is a complex task covering a few hundred transform rectifier units.

There is an upper limit of about 100 MPH for a 750V conductor rail system due to reliability of shoe contact and the amount of power that can be drawn from the system more substations could be added but that comes down to the cost / benefit equation to increase speed by 25% would mean 4 times as many substations

just out of interest... why is the passing loop at axminster so long? i know its so trains can pass at speed...but why? they have to stop at axminster anyway?

Yes, I should have written this better.  The original 22 class 159/0 sets were fitted with 4 step braking.  Apparently, this was to make them incompatible with other 'sprinters' and thus avoid them being purloined by other franchises later in life.  On delivery, they were not able to work in multiple with other classes.  I can only surmise that operational headaches and the arrival of surplus 158s from the frozen north, (reconfigured as 159/1s), have resulted in a modification allowing multiple working with other classes. 

Regarding line speeds in general, I wonder if the service on FGW (and elswhere) could be improved by a slight general increase in line speeds, I believe that in many cases speeds could be slightly increased without expensive infrastructure works, and without reducing safety standards.

It must be remembered that a speed limit of say 60, may have been imposed decades ago when many drivers took speed restrictions with a "pinch of salt". In years gone by a great many services routinely exceeded speed limits by 5 or 10 MPH without accident.
These days speed limits are strictly enforced, with drivers at risk of dismissal for all but the most trivial breaches.
A strictly enforced limit of say 65 MPH should be no less safe than a limit of 60, over which trains in practice did at least 65 and sometimes 70.

If the timings were kept as at present, but permitted speeds slightly increased, then a much more reliable service could offred, by turning late departures into on time arrivals.

the 4th step is the same as on a class 170 it gives an extra 1bar pressure in emergency,this does not stop them from running in multiple as emergency is not a step used in normal running,dont quote me on it but i believe the 159/0 still have this and it does not cause any problems when coupled as it uses a seperate train wire that other sprinters do not have.
all that happens when an emergency application occurs is 1 set will have higher brake pressures while the other is normal step3.

I doubt it had anything to do with franchises, this was back in the days of BR.  The 159s were a result of Regional Railways ordering more 158s than they needed at the same time as Network SouthEast were looking and so that part of the order was taken by Network SouthEast and they were then converted to 159s.  It's quite possible though they they were made incompatible with other sprinter units to prevent their use by other BR sectors though.

When the 159's were undergoing initial reconfiguration c1992, the plans for privatisation were well on the table. Network South East was I believe, something of a dummy run in many ways.  I can only quote depot here say, but I am led to believe that NSE foresaw the possibility of future stock moves/grabs and instigated this mod in order to keep the 159s in the sunny south.  There is a pretty solid body of opinion that insists the 159s could not run in multiple with anything else, at least in the early days, but I don't have the technical knowledge to argue the point one way or another.  It would be interesting if an expert could 'rule' on this. Perhaps smithy could come back with more info??

To my mind this would be money better spent than building a new high speed line.  If you could shave minutes off here and there all round the country and the whole country would benefit not just the folk who travel to the handful of stations served by HS2. 

It woud be a question of replacing a foot crossing with a bridge here or recanting a curve there.  It needn't be expensive if done at the same time as other renewals work. 

I agree. Parts of the WCML, GWML and ECML are 140 - 155 mph ready.

Which parts of the WCML are worthy of 155? By the time top speed is reached, braking for a curve would be required.

The only route apart from CTRL that is cleared for regular speeds in excess of 125 are stretches of the ECML where there is a max of 140 easy to spot these areas as they have a flashing green aspect, however the time table is geared for 125.  There are parts of the GWML capable of over 125 but it is not maintained to a standard above 125

There are problems for staff on the track with speeds over 125 it is difficult to get the safe sighting distance even at 125.

the 159's started life as ordinary 158's with bsi couplings but were converted to 159's by a company in scotland,they did have 4 step braking in the early days i think as part of a trial initially and it was later put to standard 3 step.
i believe there was nothing to stop them being ran in multiple despite the 4 step although network south east preffered them not to be used with other 3 step braked units,not sure why this was the case though.
the only major difference between 159's and similar 3 car 158's like the ex-tpe stuff is the toilet retention tanks and SWT have got modified driver switch and door control panels fitted now.
these days 159's can be coupled to other dmu's with compatible bsi couplings for example the 2 and 3 car 158's aquired from TPE.

Well, BR obviously thought 155 mph would be worth it.

The InterCity 250 project would have introduced non tilt 155 mph trains. With tilting, probably even more of the line.

Yes, in cab signalling is required.

No parts of the ECML operate at 140mph. That trial was dropped many many years ago!

I personally find the speed travelling on a HST between Reading & London most satisfactory ;D

Whack a few good tunes on my MP3 Player and obtain a tea from the buffet car = A relaxing and speedy journey 8)

The overall line speed limit on the Southern below Salisbury is 85mph. 60mph through Honiton if routed by the main line, 25mph through the up loop line. Think there might be a differential speed limit at Gittisham heading towards Honiton which is to do with the braking distance from the Honiton up distant to the signal controlling access to the up loop. Don't know for sure as I haven't signed the Mule for years.

The 159's did NOT have 4 step braking from new. Urban Mythology I'm afraid. They were built with standard 3 step braking which they still retain. Only difference as far as the brake controls are concerned is there is an emergency stop plunger on the secondmans side which is used during driver training and so forth. They were built as three car 158's, they would have been 158873-895 in the scheme of things, they have the same 400bhp Cummins as the 158863-872 batch of cl158. The interiors were delivered part fitted out, Rosyth Dockyard doing the conversion to 159 interior layout and fitting the first class section, toilet tanks etc.

The delay in fitting toilet tanks to the 159/1's was due to the engineering drawings for the original tanks being mislaid when Rosyth changed hands, a spare tank at Salisbury was cut up and measurements taken in order to obtain the tanks for the 159/1's.

There were thoughts about re-engineing the 159/1's to take the 400bhp Cummins although it doesn't in fact show any performance advantage over the 350bhp Cummins used on the FGW ones. The step up gears within the transmission have a different ratio which has the effect of keeping the 400 Cummins below its rated BHP. As there is more involved than swapping the engines (The transmission, rads and oil cooler have to be changed as well) I doubt this will happen.

thankyou, so basically i wasnt the only one slightly over the speed lim?.. a descrepancy which i resolved asap of corse

I won't take up space in quoting all of TSM's reply ref 4 step braking from above, but I am pleased to see this issue laid to rest.  Urban myth it may be, but a very widely believed one.  Even that constant source of information ::) Wikipedia, seems to think that 4 step braking was fitted on conversion from 158-159/0.  Thanks to TSM and smithy.

TSM may well be correct but i have it on good authority that in early days 159's did trial a 1 bar pressure increase in emergency much like turbostars in essence giving it a 4th step,the trial was later removed and they were reverted back to standard 3 step.

They never had enhanced brake pressure in emergency either. It should be remembered that Exeter men signed them when they were new. The work all went to Salisbury / Waterloo when the shadow SWT franchise was created.

It might be they have enhanced emergency braking now, I will ask a SWT Sarum driver when I see one to ask.

Diverting a little, I've noticed on HST journeys into Paddington, on occasion the train paces aircraft coming into land at Heathrow. Sometimes the train even gains on the planes. Headwinds perhaps?

OTC

According to Air New Zealand, the landing speed for a Boeing 747-400,
one of the newer long-range versions, the landing speed is 200 km/h or
124 mph.  This is the landing configuration with full flaps and slats
deployed, which slow the aircraft significantly over its "clean"
landing speed.  So possibly.  :D

Air New Zealand
"Aircraft Statistics"
http://www.airnz.co.nz/aboutus/resourcecentre/aircraft_statistics.htm

The Boeing 767-300 and 767-200 both land at 240 Km/h or 149 mph:  Only a 143 could keep up with one of those.  ;D