Additionally, in the late seventies, BR did embark on a refurbishment programme for those first generation DMUs that it had selected to continue on in service for another ten years or so: No less time than the Sprinters should have remaining now.
Was this refurbishment anywhere near as extensive as the one required to meet DDA requirements? (Removal of existing toilets, rebuilding new disabled toilets, removing large numbers of seats, possible rebuilding of the vestibule areas on Class 156/8s to have wider doors. (Chiltern power door sets had to have doors wider than the slam doors were, how much wider are single leaf sprinter doors than HST slam doors?)
You’ve just named two of the fastest accelerating DMUs in Britain (barring the Bombardier 22X family, but they’re in a different league entirely), the 150s and the 156s, and decreed that they are in some way underpowered. Have you ever actually travelled on a 150 or 156?
Yes, I have travelled on Class 150s repeatedly on various Cornish branch lines and one of the two trains per hour from my home station to Nottingham is a 156 operated service from Skegness, however I always avoid it so I don't bake thanks to the lack of air con.
Your theoretical maths surrounding power to weight ratios is not borne out by reality. The strength of the 150s and 156s comes from the fact that they are quite lightweight, due to not carrying around any unnecessary bells and whistles that would be superfluous for the sorts of routes they operate.
Such as air conditioning, if this is superfluous for the routes they operate.... why has every significant multiple unit order since privatisation had air conditioning installed, even on "inner suburban" units that would never have recieved it under BR.
Even the Class 172s used by London Overground have it, they could have easily just left out the equipment and fitted hopper windows if it was truly superfluous. Indeed is not the presence of air conditioning a primary attraction of London Overground compared to the original service?
They are also geared appropriately to provide maximum acceleration. 150s and 156s are not underpowered, it is just that modern regional DMUs are hopelessly inefficient at getting away from a standing start: The 172s are fitted with engines delivering getting on for twice as much power as the 285hp Cummins unit beneath 150s and 156s, undoubtedly expending much more fuel, and yet this has only allowed them to match the performance of the 150s that they replaced: I have seen no signs of any journey time savings becoming apparent since 172s replaced 150s on the Snow Hill lines.
Whether journey times are reduced is largely irrelevant, the very fact that journey times appear to be around the same they were in the days of Class 150 operation would seem to indicate that they are capable of keeping to timings set for the Class 150.
You are also comparing units geared for 100mph with units geared for 75mph. If we were to re-gear the Class 172 for 75mph I am sure its acceleration would be significantly improved.
These trains provide significantly enhanced capacity (due to reduced numbers of vestibules and the like per train metre), apparently to the degree that London Midland has decided to abandon 3+2 seating on the routes that have converted to Class 172 operation.
A significant fraction of the Class 150 fleet also lacks end gangways and are thus suboptimal if they are used on routes which require units to work in multiple. They are therefore poor candidates for rebuild because, as I understand it, almost the entire fleet is so used.
Meanwhile, on longer distance "regional" services the Class 156 would appear to have a good range of qualities, such as rapid acceleration to reduce travel times on slower routes. However they have longer dwell times than a Class 172 and have no advantage in acceleration.
They are also limited to 75mph which itself stymies any attempt to improve speed on secondary routes, and results in trains operating at lower speed over main line sections to reach the spurs they spend large parts of the journey traversing.
Why improve line speed on a route above SP75 if the only units available for the route are only capable of 75mph?
100mph units with the acceleration of 75mph units would drastically improve the business case for such improvements.
An entirely uniform 100mph capable fleet would be another boon operationally as you would not have the problems Northern currently have with assigning units to inappropriate services.
They can get away from a standing start a damn sight quicker than a 170 can, and are better laid out for regional services than Turbostars are.
The move in the industry is aware from end doors and towards the "commuter" layout with double leaf doors at the third positions, this is typified with the most modern "regional express" unit on the network, the Class 185.
The reduced dwell times improve timetable reliability and can in aggregate represent a low cost way to generate important journey time reductions.
The drastic improvement in the quality of door seals in recent years would seem to largely ameliorate the traditional concerns over draughts and noise, removing one of the key benefits of end doors in this speed range.
Come on then, which is it? Is it “only” eight years, or is eight years “a considerable lifetime”?
8 years is not a significant lifetime for a half million pound rebuild that will produce trains that will not produce large quantities of useful spares at the end of that time.
8 years
is a significant lifetime for a far less expensive rebuild that will involve expenditure on equipment (new transmissions) that will generate large numbers of spare parts per unit cost. (as the transmissions are similar if not identical to ones fitted to modern Turbostars).
Only to you. Meanwhile, it is evident that various areas of the rail industry have been busy planning for refurbishing the Sprinter fleet to be fully DDA compliant: FNWs’ 150 refurb has made them partially compliant, Porterbrook has a plan for the 156s, and Voith and SWT are proposing to trial a new transmission under one of SWTs’ 158s.
As far as I understand it it is not Voith who are undertaking the transmission trial, unless a second one is taking place? As I understand it is ZF.... although I could understand that Voith is desperate to avoid loosing the contract although I doubt that they can prevent it.
Partially compliant is not going to cut it, either the trains are compliant or they are not.
Just because the industry is preparing for this solution does not necessarily mean it is the optimal one, everyone knows the DfT is full of idiots who would probably baulk at the thought of new trains when they can make the current ones last a few years longer, even if in the long term it is the worse choice.
If Voith and SWT didn’t envisage a reasonable lease of life being left in the 158s, then they would probably simply aim to run the existing transmissions into the ground if they were due for withdrawal before 2020 anyway.
... again I was not aware of a second trial with a Voith tranmission.
However as I stated fitting a transmission is likely to be far less expensive than fitting brand new interiors, DDA compliant toilets and the like.
And given that at the present time there is no outlined strategy for Pacer replacement by the end of the decade, just how do you envisage around 1,000 Sprinter carriages of various classes would also be replaced by 2020 on top of this figure? Even if all the Sprinters are not made DDA compliant, you can bet your bottom dollar that dispensations will be made that allows them to operate beyond 2020.
They spammed huge numbers of brand new EMUs in a rather short period of time to beat the Mark 1 withdrawal target didn't they?
The Class 172 is a current design and could be easily massed produced at short notice, turning out ~1200 carriages in the next eight years is a tall order, but far from an impossible one.
Not making the Sprinters DDA compliant, but gaining dispensations instead, probably reduces the lifespan of the units further, since they will be a political embarrassment and will continue to age, reducing the lifespan that could be gained from a DDA refit to the point where one becomes uneconomic.
The political problems caused by allowing trains to be used on the network that cannot be used by disabled people will in the long term cause problems as disabled advocacy groups accuse the government of putting money ahead of its commitments to equality.
Therefore the trains would last a handful of years before being withdrawn and scrapped rather than being rebuilt and lasting a couple of handfuls of years.
And this is before we get into the political problems with air pollution caused by such old diesel engines in an era where modern trains face increasingly stringent emissions requirements.
Who needs the Algarve when you have Skegness! 