Class 170 question

[najaB]

Travelling on a 170 as it slowly grinds its way up Colloden, Moy and Slochd and it got me wondering - is the 170 underpowered, or is Scotrail expecting more of them than they really have any right to?

 

[Ianno87]

See also: A 170 from a standing start at Bromsgrove heading up the Lickey incline. I think they struggle with hills generally...

 

[TheEdge]

See also: A 170 from a standing start at Bromsgrove heading up the Lickey incline. I think they struggle with hills generally...

I'd think that would be a challenge for most things!

I've never noticed them to be that bad on hills. They don't seem to get any issues from the up down nature of the East Suffolk.

 

[Bungle965]

See also: A 170 from a standing start at Bromsgrove heading up the Lickey incline. I think they struggle with hills generally...

If the 170 is stopping at Bromsgrove then yes the driver has to hammer it, for it to be able to get up the gradient at a sensible speed.
I believe I read somewhere that the 170`s have a poorer power to weight ratio than other DMU`s
Sam

 

[edwin_m]

The 170 is a bit underpowered - on level track it takes almost forever to get to its nominal 100mph maximum. They are also quite heavy which particularly makes a difference when climbing gradients.

 

[47271]

They are underpowered for the HML and many a time I've had one cancelled or consolidated at Perth because they can't let it attempt the hills on two engines. I don't like the interior of 158s but they always sound and feel a lot more capable under the floor than 170s.

Not to worry, we'll have HSTs with only five mk3s to replace them in a couple of years time, so long as both power cars are working up Slochd...

 

[Bungle965]

They are underpowered for the HML and many a time I've had one cancelled or consolidated at Perth because they can't let it attempt the hills on two engines. I don't like the interior of 158s but they always sound and feel a lot more capable under the floor than 170s.

Not to worry, we'll have HSTs with only five mk3s to replace them in a couple of years time, so long as both power cars are working up Slochd...

The refurbished interior`s of the 158`s seem much better than the old ones!
Sam

 

[47271]

The refurbished interior`s of the 158`s seem much better than the old ones!
Sam

They are, but being tall and quite hefty I still find the seats too upright and lacking in legroom!

 

[Class 170101]

The 170s are under powered unfortunately. The 172s have improved on this somewhat.

 

[Philip Phlopp]

The 170s are under powered unfortunately. The 172s have improved on this somewhat.

I remember speaking to an ex AdTranz engineer, and he suggested they would have been much better with a 3 speed Voith gearbox, rather than the 2 speed one, which was already less than ideal for the 90mph Class 158. It takes the engine right out of its sweet-spot for torque, by all accounts.

The engines apparently lose turbo boost pressure relatively quickly after overhaul too, so the data plate output isn't reflective of the real world output and most units try to do 100mph with less power than a Class 158 or Class 159.

As you say, the Class 172s are a marked improvement, the gearbox is better but the entirely new engine design is the major difference, gone is the Mercedes-MAN joint venture truck engine and in comes a proper heavy duty engine optimised for generator sets, boats and indeed trains. It's set up for longer between overhauls, with much less loss in performance in the intervening period.

 

[najaB]

I remember speaking to an ex AdTranz engineer, and he suggested they would have been much better with a 3 speed Voith gearbox, rather than the 2 speed one, which was already less than ideal for the 90mph Class 158. It takes the engine right out of its sweet-spot for torque, by all accounts.

That probably explains it as they do seem to be struggling in the wrong part of the torque curve a lot of the time. Especially when trying to climb hills - you can tell it needs to change down a gear, but there isn't one to change to.

 

[Harbornite]

I remember speaking to an ex AdTranz engineer, and he suggested they would have been much better with a 3 speed Voith gearbox, rather than the 2 speed one, which was already less than ideal for the 90mph Class 158. It takes the engine right out of its sweet-spot for torque, by all accounts.

The engines apparently lose turbo boost pressure relatively quickly after overhaul too, so the data plate output isn't reflective of the real world output and most units try to do 100mph with less power than a Class 158 or Class 159.

As you say, the Class 172s are a marked improvement, the gearbox is better but the entirely new engine design is the major difference, gone is the Mercedes-MAN joint venture truck engine and in comes a proper heavy duty engine optimised for generator sets, boats and indeed trains. It's set up for longer between overhauls, with much less loss in performance in the intervening period.

That's some interesting info there. I should add that the 172's have mechanical rather than hydraulic transmission.
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Has anyone here been able to compare the performances of 170's and 172's on the Lickey by travelling on both classes up it?

 

[The Planner]

Has a 172 gone up the Lickey?

 

[Harbornite]

Has a 172 gone up the Lickey?

It is a weekly, if not daily occurrence. Coincidentally, I requested that the forums should add the BHM-HFD via Bromsgrove 172 diagrams to the frequently requested diagrams thread but this hasn't happened yet.

 

[Bungle965]

It is a weekly, if not daily occurrence. Coincidentally, I requested that the forums should add the BHM-HFD via Bromsgrove 172 diagrams to the frequently requested diagrams thread but this hasn't happened yet.

I do believe that it would be a welcome addition.
Sam

 

[PHILIPE]

I do believe that it would be a welcome addition.
Sam

Perhaps nobody has got access to them.

 

[Harbornite]

I do believe that it would be a welcome addition.
Sam

I used to have the headcodes for the weekend 172 services, but they have changed since.
--- old post above --- --- new post below ---

Perhaps nobody has got access to them.

Back in 2014/15 on sundays, 1V15 BHM-HFD 1V21 BHM HFD and 1M08 HFD-BHM were worked by 172's whenever I saw them, and 1V19 BHM-HFD was 172 worked on saturdays. This has probably changed since.

 

[IanXC]

It is a weekly, if not daily occurrence. Coincidentally, I requested that the forums should add the BHM-HFD via Bromsgrove 172 diagrams to the frequently requested diagrams thread but this hasn't happened yet.

That rather relies on someone providing the data! If someone wants to head over and post this on the Frequently Requested Diagrams Discussion & Updates Thread and provide this information, I'm sure our diligent volunteer SprinterMan will consider it's inclusion.

 

[PHILIPE]

Diagrams published on the Frequently Requested Thread should be accurate and not based on sightings. We'll have to wait for somebody in the know to provide the info.

 

[Harbornite]

Diagrams published on the Frequently Requested Thread should be accurate and not based on sightings. We'll have to wait for somebody in the know to provide the info.

Well I wouldn't be so sure about that, it's not always black and white. Almost always, the stock that's planned for diagrams is usually used but on a recent occasion, I saw a 153 and 170 on what was supposed to be a 150 job. Regarding the 172's, the most recent picture of a 172 on a Hereford service was taken in November 2015, it was one of the diagrams that had previously seen 172's on. Therefore, I'd assume that if I saw a 172 on a certain diagram, it wasn't a last-minute change, although I can't confirm whether or not 172's are still used on the same diagrams.
--- old post above --- --- new post below ---

That rather relies on someone providing the data! If someone wants to head over and post this on the Frequently Requested Diagrams Discussion & Updates Thread and provide this information, I'm sure our diligent volunteer SprinterMan will consider it's inclusion.

Indeed. I posted some diagrams on that thread that were relevant for 2015, but I haven't been able to confirm if they are still valid.

 

[scotraildriver]

We had 2 units (170431/2) re-engined a few years back with more powerful MTU engines to resolve the underpowered problem. They went like stink but unfortunately were much noisier and quite unreliable with 2 minor fires occurring so the project didn't get any further

 

[najaB]

They went like stink but unfortunately were much noisier and quite unreliable with 2 minor fires occurring so the project didn't get any further

Meh, what's the occasional fire between friends?

 

[edwin_m]

I wonder if replacing the transmission by a mechanical version with an extra gear would help, or if there just isn't enough power available.

New engines would have to meet the latest emissions regulations so are probably a non-starter (no pun intended).

 

[najaB]

Thanks for the answers. Another question that I meant to ask (I'll be doing some photo investigation as well) - is t my memory playing tricks on me, or did Scotrail's 170s used to have side-body panels that hid most of the gubbins? If so, why were they removed?

 

[scotraildriver]

Thanks for the answers. Another question that I meant to ask (I'll be doing some photo investigation as well) - is t my memory playing tricks on me, or did Scotrail's 170s used to have side-body panels that hid most of the gubbins? If so, why were they removed?

No they have always had their gubbins exposed and much work has been done over the years to try to protect equipment. A panel was fitted over the air raft to protect the isolation cocks which were prone to being damaged by flying ballast and all the electrical connections were shrink wrapped to prevent moisture ingress. The heavy snow of 2009/10 literally got into everything. Some sort of skirts might have helped but apparently not possible to retro fit.

 

[najaB]

No they have always had their gubbins exposed and much work has been done over the years to try to protect equipment.

Thanks again. I was looking at one this morning and the sides look like there *should* be panels, but I just couldn't remember them being there.

 

[SpacePhoenix]

Is the being under-powered for their weight partly why SWT got rid of their Turbostars and got in 158s to replace them?

 

[swt_passenger]

Is the being under-powered for their weight partly why SWT got rid of their Turbostars and got in 158s to replace them?

It wasn't a publicly declared reason. They mainly justified the change on having fleet commonality and having through gangways when multiple working in up to 10 car formations.

 

[satisnek]

The impression I get is that the 170s lose out in the mid-speed range just before the transmission changes into direct drive (or whatever it's called), where the efficiency of the torque converter has tailed off, and then they under-rev a bit afterwards? Perhaps they would have been better with a 90mph rating and a slightly lower changeover speed? Certainly, there's no problem at low speed - I've had one on an evening all-shacks service from Kidderminster to Birmingham, where I was sat in the right place to see the platform displays, and it kept time perfectly.

As for the 172s, I'm sure they can get up to 100mph a lot quicker but suffice to say they've never done this on the Stourbridge route. I can't help feeling that they would have been much better with a 75mph 'Sprinter type' transmission. As things are, their performance doesn't strike me as any better than a healthy 150. Incidentally, I don't think that they have a purely mechanical transmission - 'first gear' seems to be some kind of CVT drive, with fixed gear ratios in subsequent steps.

 

[dk1]

I'd think that would be a challenge for most things!

I've never noticed them to be that bad on hills. They don't seem to get any issues from the up down nature of the East Suffolk.

Totally agree. I never lose time across that route with its constant speed restrictions & far from flat terrain.