difference between 168/1 and 2s and 170s and 171s

[ChilternHenry]

What are the main differences between the 168s and 170s and 171s, excluding the 168/0, other than couplings. Any differences in power? And if not, why the need for so many subclasses

 

[sprinterguy]

There's essentially no difference between 168/1s and 168/2s and class 170s of the same period (The 170 design has gone through a couple of minor detail changes during it's time in production), except that all of the 168s are fitted with Tripcocks required to operate over LU lines from Amersham, and the differing interiors.

Chiltern were the first recipient of what turned out to be Turbostar trains in the form of the 168/0s: I suppose that Adtranz, as they were then, felt that the main tranche of Turbostars that entered service afterwards with other operators were different enough to the 168/0s, certainly in terms of cab styling, to christen them as class 170s, while it made sense for Chiltern to continue to number their units in the class 168 series.

 

[Derbyshire Gra]

It's largely to do with coupling compatibility. From Network South East days, 165 and 166 classes were set up with a different pin arrangement to prevent them being operated on Regional services. The 168s have coupling configuration with the 165/166s.
170s have full coupling configuration with the 14x / 15x ex Regional Railways Units, but cannot multi with 165/166 or 168s.
171s are a further coupling development to give compatibility with the Dellner Head used throughout Southern on classes such as 377. This was a Southern driven initiative for simplicity of operation on their patch.
It would be technically possible for any of the three types to be reconfigured to one of the others, although in the case of to/from 171s, they would need to have the coupler heads changed as well as the pin configuration.

 

[LNW-GW Joint]

It's largely to do with coupling compatibility. From Network South East days, 165 and 166 classes were set up with a different pin arrangement to prevent them being operated on Regional services. The 168s have coupling configuration with the 165/166s.
170s have full coupling configuration with the 14x / 15x ex Regional Railways Units, but cannot multi with 165/166 or 168s.
171s are a further coupling development to give compatibility with the Dellner Head used throughout Southern on classes such as 377. This was a Southern driven initiative for simplicity of operation on their patch.
It would be technically possible for any of the three types to be reconfigured to one of the others, although in the case of to/from 171s, they would need to have the coupler heads changed as well as the pin configuration.

Very interesting explanation.
So when 16x units end up further west with GW after being displaced by EMUs, they will have to be modified to interwork with 15x units?

 

[t_star2001uk]

Also the 168 series have ATP fitted as well....

 

[TDK]

There's essentially no difference between 168/1s and 168/2s

168/1's compared to 168/2's are quite different. 168/2's have a Different body shell, different fuel management system, they have mitrac, slightly different interior, different cab aircon. There are a lot more differences than you think.

 

[sprinterguy]

168/1's compared to 168/2's are quite different. 168/2's have a Different body shell, different fuel management system, they have mitrac, slightly different interior, different cab aircon. There are a lot more differences than you think.

Due to a grammatical error on my part, you have misunderstood my post: What I should have said is that there's essntially no difference between 168/1s or 168/2s and class 170s of the same period: I knew that the Turbostar design had "evolved" between the 168/1 and the 168/2 build, and note the differing interiors and "detail differences".

However I wil readily admit that I was not aware of the extent of the differences between 168/1s and 168/2s, so thanks for the additional information. There are many things that I overlooked in my initial post by the looks of it! However, different body shells? The cab ends are slightly different, but what differences are there in the bodyshells?

 

[O L Leigh]

However, different body shells? The cab ends are slightly different, but what differences are there in the bodyshells?

None. They are identical in all major respects.

Heck, there are just as many combinations of cab A/C, light cluster arrangements, air dam designs, cab layout and wiring looms just within the Cl170 fleet. However, it doesn't amount to a hill of beans and certainly doesn't make any difference to them operationally.

I can't comment on the arrangement of pins within the coupler blocks of Cl165s and what effect this might have for interworking with Cl170s, but don't forget that the last two (or three) of the batch were paid for by Regional Railways to operate the Cotwolds Line service from new. There was talk at the time that they would be painted in Regional Railways livery and operate as a separate sub-fleet, but in the end they were all painted in NSE livery and operated as a common fleet. This may have had a bearing on the coupler pin arrangement as it may have been envisaged that they should be capable of working with Sprinter classes.

That said, things change. The use of ATP may have necessitated a change in the coupler pin arrangements that may now prevent them working with non-ATP fitted stock simply due to coupler incompatibility.

However, the OPs question appears to have been answered. Cl168, Cl170 and Cl171 DMUs are identical in all important aspects (although there are detail differences). The Cl170 can be considered the "basic" design with the other two being variants. Cl168s have ATP and Tripcocks fitted to permit working over the Met Line and Chiltern route while the Cl171s have had the BSI coupler changed for Delners to permit limited compatibility with Southern's fleet of EMUs.

O L Leigh

 

[Cherry_Picker]

That said, things change. The use of ATP may have necessitated a change in the coupler pin arrangements that may now prevent them working with non-ATP fitted stock simply due to coupler incompatibility.

That brings back the 172 question.

I presume LM 172 and Chiltern 172's can couple to each other? If they can't, shouldn't they be a different class from each other?

If so, a LM 172 can couple to a 170. A Chiltern 172 can couple to a 168.
Can a Chiltern 172 couple to a 170? A LM 172 to a 168?

 

[O L Leigh]

Are they not at least different sub-classes...?

I recall hearing a tale of a Central Cl170 having to go forward to assist a failed MML Cl170. It was the only way to get the job moving again, so off the CT unit went. When they coupled them up they realised that they were going to be there a while as they couldn't get the two units to talk to each other. It later transpired that the coupler pin arrangements were slightly different between the two fleets. Central had specified their units to have backward compatibility with their Sprinter fleet while MML had never needed this facility. The only people who knew were Bombardier. When XC was created a lot of time was spent modifying the Cl170/1 fleet to ensure full compatibility with the rest of the fleet, what with coupler pins, SDO and the rest. Even now, I've heard that there is a person employed full-time at Tyseley to try and work out how these former MML units are wired.

As for Cl172s, I'm not sure that LM work them in multi with anything else. I believe there were coupling trials prior to them entering service, but I have never seen them doubled up with anything other than another Cl172. Yes I imagine that they could multi with another operator's fleet if need be but, as with the Cl170 incident I heard about, it may be more complicated than that. There has been more than one instance where units have coupled up only to find that there were inconsistencies between the two with regard to the wiring. Often these issues were totally unexpected. I suppose from an operational standpoint it doesn't really matter. The chances that these two fleets will ever meet in such circumstances is surely slim anyway.

O L Leigh

 

[sprinterguy]

Are they not at least different sub-classes...?

Yes they are: The Chiltern units occupy the class 172/1 sub-class, while the 2 and 3-car London Midland units occupy the 172/2 and 172/3 sub-classes respectively.

As for Cl172s, I'm not sure that LM work them in multi with anything else. I believe there were coupling trials prior to them entering service, but I have never seen them doubled up with anything other than another Cl172.

The 172s have worked in multiple with class 153s before, but the practice has not been perpetuated in passenger service as the corridor connection between the two units has to remain locked due to differences in floor height. There is still one ECS move that calls for a 153 to work in multiple with a 172, though.

 

[jopsuk]

Are the LO 172/0 fleet wired up as per the Chiltern /1s or the LM /2 and /3s? Or a third way?
As an aside, LM's sub fleet numbering is rather neat in easily denaoting which are their 2 car and which are their 3 car units. Far neater than the numbering of the 170s, which is these days a mess- XC have 2 and 3 car /1s, 2 car /5s and 3 car /6s

 

[150219]

Are the LO 172/0 fleet wired up as per the Chiltern /1s or the LM /2 and /3s? Or a third way?
As an aside, LM's sub fleet numbering is rather neat in easily denaoting which are their 2 car and which are their 3 car units. Far neater than the numbering of the 170s, which is these days a mess- XC have 2 and 3 car /1s, 2 car /5s and 3 car /6s

LO 172 fleet is compatible with the CRCL 172 fleet, which are both compatible with 165/166 units. None of the these units are compatible with any other 2nd generation DMUs, including LM 172 units, which is due to a different arrangement of the coupler pins. Although in emergencies the coupler pin box can be retracted and only mechanically coupled.

IIRC the ATP used a pin that was spare anyway (N.B. The Thames turbos didn't and don't have ATP fitted) and there are a few deliberate alterations to the other pins, purely to keep the Turbo fleet retained in one pool.

 

[TEW]

LO 172 fleet is compatible with the CRCL 172 fleet, which are both compatible with 165/166 units. None of the these units are compatible with any other 2nd generation DMUs, including LM 172 units, which is due to a different arrangement of the coupler pins. Although in emergencies the coupler pin box can be retracted and only mechanically coupled.

Chiltern 172s can and do couple to the 168s as well, and presumably LO ones could also if required.

 

[Cherry_Picker]

I was fairly certain I'd seen a 172 coupled to a 170 before, at least on Tyseley. Perhaps I was mistaken.

 

[TEW]

LM172s should be able to couple to LM170s, they both have the Sprinter type pin configuration.

 

[ChilternHenry]

I was fairly certain I'd seen a 172 coupled to a 170 before, at least on Tyseley. Perhaps I was mistaken.

No you're not mistaken, seen it quite a few times actually, i wouldn't say its a common occurrence but its not that rare either.

 

[O L Leigh]

Just a word of caution about these sightings. Combinations can be made with ECS that cannot be made in service. For example, you can multi a Cl315 with a Cl317 but only for ECS or assistance purposes and never in service. There are limits on compatability.

And I know where this discussion is heading next.

O L Leigh

 

[AlexS]

Class (172/2/3)s/(153)s/(170/5/6)s are all fully compatible with each other within the London Midland fleet, I can't say about others. I've seen various permutations of them kicking around, the last time I was on the Snow Hill lines I passed a 170/172 combination in service. They've also been known to work with their 150s back before they were withdrawn from squadron service.

Here is an image credited to 'Techniquest' of this forum of a 170 and 172 in passenger service, in multi, at Hereford.

Now the 170s have booked jobs on the Snow Hill lines it would have been silly for them not to be compatible with the 172s on such an intensively worked route (not silly beyond the grasp of the modern railway, but I personally am quite satisfied they all will interwork nicely).

Whether the old adage about a 170 must never be sandwiched by Sprinters still applies I don't know (I believe that causes electrical problems).

There's plenty of similar electric coupling issues about, apparently the middle door panels recently fitted to EMT 156s won't work when the unit is coupled up in multiple, for example.

 

[WillPS]

172s can work in multiple with both BSI formats (168 type and 170 type), I've read that this is enabled through a switch but I don't know if this is something available to a driver or something which has to be set by the depot/Bombardier.

 

[Qwerty133]

172s can work in multiple with both BSI formats (168 type and 170 type), I've read that this is enabled through a switch but I don't know if this is something available to a driver or something which has to be set by the depot/Bombardier.

I would guess at bombardier as I can remember a twitter conversation with LM and Chiltern and they said they couldn't couple their 172s

 

[paul1609]

It's largely to do with coupling compatibility. From Network South East days, 165 and 166 classes were set up with a different pin arrangement to prevent them being operated on Regional services. The 168s have coupling configuration with the 165/166s.
170s have full coupling configuration with the 14x / 15x ex Regional Railways Units, but cannot multi with 165/166 or 168s.
171s are a further coupling development to give compatibility with the Dellner Head used throughout Southern on classes such as 377. This was a Southern driven initiative for simplicity of operation on their patch.
It would be technically possible for any of the three types to be reconfigured to one of the others, although in the case of to/from 171s, they would need to have the coupler heads changed as well as the pin configuration.

As i understand it the 2 car 171s can be quite easily changed to 170 configuration but the 4 car units would require major rewiring to achieve this. I believe that southern wanted to make swap the middle cars of some units to make up a number of 3 car units but this had to be abandoned because of the complexity of the wiring changes required.

 

[150219]

LO 172 fleet is compatible with the CRCL 172 fleet, which are both compatible with 165/166 units. None of the these units are compatible with any other 2nd generation DMUs, including LM 172 units, which is due to a different arrangement of the coupler pins. Although in emergencies the coupler pin box can be retracted and only mechanically coupled.

IIRC the ATP used a pin that was spare anyway (N.B. The Thames turbos didn't and don't have ATP fitted) and there are a few deliberate alterations to the other pins, purely to keep the Turbo fleet retained in one pool.

Reading some of the replies I don't think I made myself clear there, so apologies. The LO 172+CRCL 172 can couple to 165/166 units and these units can not couple to any other units, without the electrical box being retracted.

LM 172s can couple to anything other compatible 2nd Generation units (153, 156, 158, 170, etc., etc.), but not to the 165/166/LO 172+CRCL 172 fleets without the electrical box being retracted.

 

[TDK]

If the ATP is fed through the couplings I doubt that a LM 172 could couple to a Chiltern 172 as in service electrically however is the pins for train wire 4, door interlock etc are compatible they could couple for emergency recovery maybe, unless someone has the configuration of the Coupler electrical boxes to hand we will never know unless it is tried.

 

[Class172]

Yes, class 170s and 172s can work in multiple. There have been a number of services over the past two weeks with such combinations. If anything I would've thought their differing transmissions may have caused a problem.

 

[Cherry_Picker]

Why? .

 

[jopsuk]

First generation hydraulics and mechanicals had issues working together- presumably modern control systems/automatic gearboxes have put paid to the gear change problems

 

[TDK]

First generation hydraulics and mechanicals had issues working together- presumably modern control systems/automatic gearboxes have put paid to the gear change problems

150s and 158's have a different change over speed on the voith gearbox as do 170's & 153's they seem to work ok

 

[Cherry_Picker]

Bump to spread a rumour. There might be a few less 172s on Chiltern before much longer. There might be a few less 170/4s on Scotrail and a few 'new' 168/3s on Chiltern too.

 

[Old Hill Bank]

Bump to spread a rumour. There might be a few less 172s on Chiltern before much longer. There might be a few less 170/4s on Scotrail and a few 'new' 168/3s on Chiltern too.

Might the rumour say that the 172s will be fitted with gangway ends and get painted green?