Chiltern MK5s Starting 2026 (non speculative updates thread)

[Peter Sarf]

Agreed, TPE did regularly rotate the sets.

Inaccurate thread title, unless Chiltern are introducing sleeper trains to their network, it should really be ‘Mk5A’

I agree, the Chiltern bit is strictly superfluous in the fleet name if the correct sub Mk5 bit "a" is added to distinguish from sleepers etc and would help me remember it is "a" !.
The "Chiltern" bit should be in the title but to indicate they are the current operators of the Mk5a's.

That's enough detail for/from me.

I will look forward to Chiltern rotating the Mk5a's so I can get 12802, if it stays in CH06.
I also want to get a ride on the Mk5a's from Marylebone to somewhere like Birmingham.

 

[MerlinRail 804]

Would be nice to have a name though, I don’t think that naming them are particularly gimmick-y in my eyes, but I understand why some do!

The best I've come up with at 3AM one day was "Comodia", a slight spin on the Spanish word for comfort. Ironic, I know!

 

[FrontSideBus]

The best I've come up with at 3AM one day was "Comodia", a slight spin on the Spanish word for comfort. Ironic, I know!

Too close to commode though! Would certainly sum up the ride quality!

 

[172007]

Chiltern certanly seem to extremely organised an no bad word or any issues have been heard on the grapevine at all. They seem to be out crew training reguarly with seemingly no interuptions.

 

[Peter Sarf]

Chiltern certanly seem to extremely organised an no bad word or any issues have been heard on the grapevine at all. They seem to be out crew training reguarly with seemingly no interuptions.

Heaven forbid - something well planned and going smoothly.

Credit where its due (and I hope I have not jinxed it). So far no rash promises ?.

 

[Johnhayworth21]

Is there an entry into service date for these yet?

 

[Class 466]

Chiltern certanly seem to extremely organised an no bad word or any issues have been heard on the grapevine at all. They seem to be out crew training reguarly with seemingly no interuptions.

I mean the cracking issue won’t have magically disappeared and some daily test runs do not equal a full fleet in service. They’re still CAF.

 

[sjpowermac]

I mean the cracking issue won’t have magically disappeared and some daily test runs do not equal a full fleet in service. They’re still CAF.

It has all gone remarkably quiet on the issue of Mk5A cracks. To be fair, 12 of the 13 sets were used in service with TPE after the discovery of the cracks, but it’s surprising nothing has been mentioned on this topic.

 

[PLY2AYS]

It has all gone remarkably quiet on the issue of Mk5A cracks. To be fair, 12 of the 13 sets were used in service with TPE after the discovery of the cracks, but it’s surprising nothing has been mentioned on this topic.

Am I right in thinking the cracks issue arose around the same time as the IETs? Both seemed to just fade away with not much news. Unless I’m mistaken of course… can’t say I followed either that closely.

 

[sjpowermac]

Am I right in thinking the cracks issue arose around the same time as the IETs? Both seemed to just fade away with not much news. Unless I’m mistaken of course… can’t say I followed either that closely.

The Mk5A cracks were later, June 2023. After inspection the Mk5A sets were released back into traffic, but with checks to be undertaken every 14 days (initially) though this was later relaxed to 45 days.

 

[172007]

I Thought the cracks were simular to the class 80X and also 19X trains where all the underfloor equipment is supported with a T shaped hanger in a rail and the suspension components were puttimg too much stress on the rails. The solutions were an extra long shim to spread the load / stress over more of the slot with extra T hangers.

 

[43096]

I Thought the cracks were simular to the class 80X and also 19X trains where all the underfloor equipment is supported with a T shaped hanger in a rail and the suspension components were puttimg too much stress on the rails. The solutions were an extra long shim to spread the load / stress over more of the slot with extra T hangers.

They are different to the 80x cracking.

 

[FrontSideBus]

Was something to do with the attachment point for the bogie yaw damper?
I'm sure Northern had a similar problem on their CAF units and you still see 331's and 195's going around with the dirt cleaned from around that area so they are clearly keeping a close eye on those too.

 

[sjpowermac]

Was something to do with the attachment point for the bogie yaw damper?
I'm sure Northern had a similar problem on their CAF units and you still see 331's and 195's going around with the dirt cleaned from around that area so they are clearly keeping a close eye on those too.

Yes, the Mk5A cracks were (are?) in the yaw damper attachment points.

 

[172007]

Yes, the Mk5A cracks were (are?) in the yaw damper attachment points.

So the slot with the T bar attachment i mentioned in post 791

 

[sjpowermac]

So the slot with the T bar attachment i mentioned in post 791

Yes, correct.

 

[172007]

Whilst not Mk5's but 68028 worked 3Q70 today from Stourbridge to Banbury with a Mk3 set (68012 on rear). Is this the first time one of the former TPE loco's has worked anythink other than Mk5's for Chiltern?

68028 looks smart with the yellow front tbh. Possibly better than the dark blue. Be interesting to see a Mk5 DT with yellow on front.

 

[MerlinRail 804]

68028 looks smart with the yellow front tbh. Possibly better than the dark blue. Be interesting to see a Mk5 DT with yellow on front.

I honestly prefer the dark blue front. The yellow makes it look dated IMO

 

[Jacob Porrett]

Whilst not Mk5's but 68028 worked 3Q70 today from Stourbridge to Banbury with a Mk3 set (68012 on rear). Is this the first time one of the former TPE loco's has worked anythink other than Mk5's for Chiltern?

68028 looks smart with the yellow front tbh. Possibly better than the dark blue. Be interesting to see a Mk5 DT with yellow on front.

Believe 68012 failed yesterday hence the strange movement.

 

[43 302]

Believe 68012 failed yesterday hence the strange movement.

It failed on Christmas Eve. Embarrassing it took this long to do anything about, meanwhile various formations of 165s have been used instead with the only Mk3 set in use missing a coach. All whilst the WCML is blocked. Very poor from Chiltern.

 

[CR165022]

The 165 formations are booked to be fair. A lot of the Birmingham services are pathed as them during the blockade. They have extra capacity over 168s which is why they're somewhat preferred when the WCML is blocked.

 

[PLY2AYS]

It failed on Christmas Eve. Embarrassing it took this long to do anything about, meanwhile various formations of 165s have been used instead with the only Mk3 set in use missing a coach. All whilst the WCML is blocked. Very poor from Chiltern.

Why is the time between it failing and this particular move embarrassing?

And does anyone know if TOCs have an obligation to run sets in a particular formation during things like engineering works/service disruption? Presumably these things are planned well in advance or as contingency measures, but I’m curious to know if there’s a specific target operators need to meet.

 

[43 302]

Why is the time between it failing and this particular move embarrassing?

For the reasons I said. The WCML is closed and Chiltern have been short-forming trains.

== Doublepost prevention - post automatically merged: 1 Jan 2026 ==

The 165 formations are booked to be fair. A lot of the Birmingham services are pathed as them during the blockade. They have extra capacity over 168s which is why they're somewhat preferred when the WCML is blocked.

They are not booked on the MK3 diagrams for which they have been covering since 68012 failed. Until today only 68008 has been out with the other diagram being 165s or 165 + 168.

 

[CyrusWuff]

And does anyone know if TOCs have an obligation to run sets in a particular formation during things like engineering works/service disruption? Presumably these things are planned well in advance or as contingency measures, but I’m curious to know if there’s a specific target operators need to meet.

As far as I'm aware, there's no requirement for Operators not directly affected by Engineering Work to run anything other than their base timetable.

Had Chiltern chosen that option, however, it would have been even more unpleasant given their off-peak service between London and Birmingham is generally 1tph and only a single unit.

 

[PLY2AYS]

For the reasons I said. The WCML is closed and Chiltern have been short-forming trains.

== Doublepost prevention - post automatically merged: 1 Jan 2026 ==

No, you said:

It failed on Christmas Eve. Embarrassing it took this long to do anything about

Indicating that the timing was somehow embarrassing… I’m curious as to why that is the case.

As far as I'm aware, there's no requirement for Operators not directly affected by Engineering Work to run anything other than their base timetable.

Had Chiltern chosen that option, however, it would have been even more unpleasant given their off-peak service between London and Birmingham is generally 1tph and only a single unit.

Seems as though the Mk5s entering service, has unfortunately come at a later than ideal time for the engineering works this year and passengers are feeling the effects of that.

It’ll be interesting to see how this changes under GBR moving forward (by this I mean contingencies and other lines offering additional/fortified services)

 

[150219]

It failed on Christmas Eve. Embarrassing it took this long to do anything about, meanwhile various formations of 165s have been used instead with the only Mk3 set in use missing a coach. All whilst the WCML is blocked. Very poor from Chiltern.

Embarrassing you may say, but it's a strong choice of phrase presumably without having the knowledge of what was wrong and who was able to fix it. Failing on Christmas Eve means that two days are immediately lost and arranging a suitable transfer move when train crew are working to the max isn't as easy as saying 'let's go'. A unit substitution instead of a loco hauled set also means more seats provided, depending on the formation of the service as diagrammed.

 

[43 302]

Indicating that the timing was somehow embarrassing… I’m curious as to why that is the case.

I'm not entirely sure what you're missing here. The quicker the set and errant loco were rescued, the quicker that set could have been pressed into service again? No one would expect anything to be done on the 25th or 26th, but I don't see why it took five days to send a loco to drag the set back to Banbury meanwhile trains booked for 6 Mk3 coaches are running with 3/4/5/6 DMU carriages.

 

[warwickshire]

I'm not entirely sure what you're missing here. The quicker the set and errant loco were rescued, the quicker that set could have been pressed into service again? No one would expect anything to be done on the 25th or 26th, but I don't see why it took five days to send a loco to drag the set back to Banbury meanwhile trains booked for 6 Mk3 coaches are running with 3/4/5/6 DMU carriages.

Other reasons , was the set due a exam, plus other mk3 sets exams, plus, with the Wcml being closed at Hanslope junction, resources already planned elsewhere and already tied,,
Train paths already planned and booked.,
Drs locomotives and resources, streteched to limit, Train paths was VSTP, very short term planning. Network Rail cannot create the paths in a split second.

Rog had to do moves rather than via Drs, The moves involved for this rescue and to get, 68015 back to Chiltern., and 68012 to Crewe, was quite excellent and handled very well.

Chiltern have done remarkably well,
However can you imagine the cahos if a mk3 set had broke down in the middle of Nowhere, leaving Hundreds if not a few thousands of stranded diverted Wcml passengers trapped on Trains, stranded on Stations etc.

Far more important, to run this way,
Obvious reasons, not the time for a Christmas diesel gala,
Plenty of time, and many years ahead to sample the class 68s anyway.

 

[dooton]

I'm not entirely sure what you're missing here. The quicker the set and errant loco were rescued, the quicker that set could have been pressed into service again? No one would expect anything to be done on the 25th or 26th, but I don't see why it took five days to send a loco to drag the set back to Banbury meanwhile trains booked for 6 Mk3 coaches are running with 3/4/5/6 DMU carriages.

There are multiple parties involved. The loco needed to be checked by the engine manufacturer who then stated it needed to be recovered. Then driver availability, possessions and the maintainers availability all contributed to the recovery.

No TOC wants to leave a broken train stopped for any longer than absolutely necessary.

 

[warwickshire]

IJ47 1637 London Marylebone to Stourbridge jct, has been sat down outside of Bicester for around 40 minutes with 68013 and 82305 DVT.

If 68028 comes to the rescue, this will be on Chiltern, a first time, a ex Transpennie Locomotive has hauled a Chiltern service, ablight a mk3, resuce mode.

But the first Class 68 ex Transpennie locomotive, to haul a service in passenger service, ironically not a mk5 but a mk3,

New years Day, new year, Honours could, well beckon for 68028, maybe?.