How is maintenance organised for different asset types?

[GraphitProjekt]

I recently came across this shapefile dataset from 2023 with shapefiles for various Network Rail subdivisions: Region, Route, Maintenance Delivery Unit (MDU), Track Maintenance Engineer (TME) and Track Section Manager (TSM) - each fitting within the divisional level above it, although they are some integration of layers sometimes (TMEs with only one TSM etc).
From that I've made this map to try and represent the information for Wales & Western. Nothing special about W&W, it's just where I've happened to start and am interested in covering the rest of the Routes.
View attachment Wales & Western region-01.png



However, I'm not entirely sure what this information actually means!

Especially since I came across this ORR document from 2022 about how maintenance is structured. A lot of it is complex management speak but there was some interesting information about the different role types involved.

Initially I had assumed that the TME level is equivalent to the "IME" position in the org chart above. But I now notice that the IME has an asterisk referring to "1 per MDU". I think in this context, MDU refers to the top level divisions within a route (for Western: East, Central, South; for Wales: Cardiff, Shrewsbury). So if there's only one IMDM and only one IME per MDU then the TME subdivisions in the dataset might only refer to specifically the Track/Pway department, and similar for the inner TSM divisions.

So tldr: do the TME/TSM subdivisions in the above map apply only to Track or are there other disciplines organised according to those same areas (or do other asset types have totally different subdivisions)?

For reference, I'll include tables of all the MDU/TME/TSM divisions for the other regions that I haven't made a map of (yet) just so that people who know areas other than W&W can comment on that. Keep in mind this is 2023 data, I believe since then the whole of the WCML has become its own Route, but at that time there was just a WCML South.

Spoiler: Scotland Maintenance Delivery Unit Track Maintenance Engineer Track Section Manager Motherwell [MDU] Motherwell [TME] Motherwell [TSM] Carstairs Dumfries Irvine [TME] Irvine [TSM] Maybole Paisley Glasgow [MDU] Glasgow (West Highland Line) [TME] Crianlarich Fort William Glasgow East [TME] Glasgow East [TSM] Glasgow West Dunbarton Glasgow Central [TME] Glasgow Central [TSM] Glasgow South Edinburgh [MDU] Edinburgh [TME] Waverley Edinburgh Park Portobello Inverkeithing [TME] Inverkeithing [TSM] Stirling Perth [MDU] Perth [TME] Perth [TSM] Dundee Inverness [TME] Inverness [TSM] Dingwall Keith Helmsdale

Spoiler: North West & Central Route Maintenance Delivery Unit Track Maintenance Engineer Track Section Manager North West Lancashire & Cumbria Appleby [TME] Appleby [TSM] Cumbrian Coast Preston [TME] Preston [TSM] Kirkham Carnforth [TME] Carnforth [TSM] Carlisle [TME] Carlisle [TSM] Blackburn [TME] Blackburn [TSM] Liverpool [MDU] Liverpool [TME] Edge Hill Chester Warrington [TME] Warrington [TSM] Wigan Crewe Crewe North Crewe South Mersey [TSM] Mersey [TSM] Manchester Manchester South Piccadilly Wilmslow Manchester North Victoria Bolton Manchester East Chinley Guide Bridge WCML South Stafford [MDU] Stafford [TME] Stafford [TSM] Stoke Nuneaton [TME] Nuneaton [TSM] Bletchley [MDU] Bletchley [TME] Leighton Buzzard Milton Keynes Rugby Rugby South Rugby North Northampton Euston [MDU] Euston [TME] Euston [TSM] Stonebridge Park Watford [TME] Watford [TSM] Central Saltley [MDU] Saltley [TME] Saltley [TSM] Stourbridge Banbury [TME] Banbury [TSM] High Wycombe [TSM] Worcester [TME] Worcester [TSM] Sandwell & Dudley [MDU] Sandwell & Dudley [TME] Sandwell & Dudley [TSM] Walsall Coventry

Spoiler: Southern Route Maintenance Delivery Unit Track Maintenance Engineer Track Section Manager Kent London Bridge [MDU] London Bridge [TME] London Bridge [TSM] Hither Green [TME] Hither Green [TSM] Dartford [TME] Dartford [TSM] Orpington [MDU] Orpington [TME] Orpington [TSM] Herne Hill Tonbridge [TME] Tonbridge [TSM] Ashford [MDU] Ashford [TME] Ashford [TSM] Faversham Medway East Kent Sussex Brighton [MDU] Brighton South Brighton [TSM] Barnham Brighton North Horsham Three Bridges Croydon [MDU] Croydon North Croydon [TSM] Victoria Croydon South Norwood Wessex Wessex Inner Clapham [TME] Clapham [TSM] Waterloo Feltham [TME] Feltham [TSM] Wimbledon Woking [TME] Woking [TSM] Guildford Wessex Outer Eastleigh [TME] Eastleigh [TSM] Southampton Basingstoke [TME] Basingstoke [TSM] Havant Salisbury [TME] Salisbury [TSM] Yeovil Bournemouth [TME] Bournemouth [TSM]

Spoiler: Eastern Route Maintenance Delivery Unit Track Maintenance Engineer Track Section Manager East Coast Kings Cross Finsbury Park [TME] Finsbury Park [TSM] Hitchin [TME] Hitchin [TSM] Peterborough Peterborough South [TME] Peterborough South [TSM] Peterborough North [TME] Peterborough North [TSM] Doncaster [MDU] Doncaster [TME] Doncaster East Doncaster West Grantham Darlington [MDU] Darlington [TME] Darlington [TSM] York (East Coast) Newcastle [MDU] Newcastle [TME] Newcastle [TSM] Morpeth [TME] Morpeth [TSM] North & East Sheffield [MDU] Sheffield [TME] Sheffield South Sheffield North Retford Barnetby [TME] Barnetby [TSM] Leeds [MDU] Leeds [TME] Leeds [TSM] Shipley Wakefield [TME] Wakefield [TSM] Huddersfield York [MDU] York [TME] York (Central) Hull Knottingley [TME] Knottingley West Knottingley East Middlesbrough [MDU] Middlesbrough [TME] Middlesbrough West Middlesbrough East Heaton East Midlands Bedford [MDU] Bedford [TME] Bedford [TSM] Kettering Luton [TME] Luton [TSM] Cricklewood Derby [MDU] Derby [TME] Derby [TSM] Burton Nottingham [TME] Nottingham [TSM] Loscoe Lincoln [TME] Lincoln [TSM] Sleaford Leicester [TME] Leicester [TSM] Oakham Trent Anglia Romford [MDU] Romford [TME] Liverpool Street Stratford Shenfield Barking [TME] Barking [TSM] Leigh-on-Sea Tottenham [MDU] Tottenham [TME] Tottenham Hale Camden Broxbourne Ely [TME] Ely [TSM] March Ipswich [MDU] Ipswich [TME] Ipswich [TSM] Colchester Norwich [TME] Norwich [TSM] Lowestoft

Spoiler: Wales & Western Route Maintenance Delivery Unit Track Maintenance Engineer Track Section Manager Western East West Ealing [TME] West Ealing [TSM] Paddington Reading [TME] Reading [TSM] Slough Central Swindon [TME] Swindon [TSM] Didcot Bristol [TME] Bristol [TSM] Parkway Gloucester South Westbury [TME] Westbury [TSM] Newbury Exeter Newton Abbot Taunton Plymouth Tavistock Jnc Truro Wales Cardiff [MDU] Cardiff [TME] Cardiff [TSM] Newport [TME] Newport [TSM] Swansea Port Talbot Llanelli Haverfordwest Shrewsbury [MDU] Shrewsbury [TME] Shrewsbury [TSM] Llandudno Hereford [TME] Hereford [TSM] Machynlleth Llandrindod

 

[mcmad]

In general, there is an equivalent 'x'ME role for the Signalling, E&P and sometimes off-track. Depending on the number of assets E&P can sometime be DU level. Structures and telecoms are usually managed at Region level, the exact boundaries may not match the track boundaries again depending on asset volumes.

The various ME's report into the IME at the MDU level.

 

[Bald Rick]

Usually there will only be one TME per Maintenance Delivery Unit, although occaisonally two. The next layer, Section Managers, will be specific to each discipline, depending on the the and quantity of asset (and therefore maintenance work).

For example, in a Delivery unit the TME might have 4 Track Section Managers, but the SME covering the same delivery unit might have 6 Signalling Section Managers.

 

[GraphitProjekt]

I see, so E&P is more often at the MDU level. I would imagine perhaps in Southern Region E&P is more often at the lower level. Does E&P include OLE as a "sub-department" or is that separate?

There is something a bit confusing about how the term MDU refers to the top level division, but the divisions inside of it are still called DUs. I recall that there is a rather large and prominent building at Colchester called "Colchester Maintenance Delivery Unit", except that Colchester is a track section of the Ipswich track maintenance engineer area which itself is part of Ipswich MDU.

It would be great to see a list of DUs and which departments are present there. Norwich DU is split across different buildings down Lower Clarence Rd and so the individual departments announce themselves on the street. I can see Pway, S&T, Offtrack, Operations (so MOMs I guess) and interestingly Telecoms (though presumably not an organisational subdivision of Eastern telecoms)

 

[alxndr]

The boundaries of each discipline differ. The delivery unit boundaries tend to stay broadly the same between each discipline (although can different, Swindon pway/track and Swindon S&T used to have different boundaries so that made the boundary between Western Central and Western West* DUs differ).

The maintenance engineer boundaries can differ. In my DU one STME has only one S&T section. That section is covered by two main pway sections that fall under one TME but crosses into another pway area on one boundary and another DUs TME area on the other border.


* was it renamed at some point? I always thought it was West but your map has it as South.

 

[Bald Rick]

I see, so E&P is more often at the MDU level. I would imagine perhaps in Southern Region E&P is more often at the lower level. Does E&P include OLE as a "sub-department" or is that separate?

There is something a bit confusing about how the term MDU refers to the top level division, but the divisions inside of it are still called DUs. I recall that there is a rather large and prominent building at Colchester called "Colchester Maintenance Delivery Unit", except that Colchester is a track section of the Ipswich track maintenance engineer area which itself is part of Ipswich MDU.

It would be great to see a list of DUs and which departments are present there. Norwich DU is split across different buildings down Lower Clarence Rd and so the individual departments announce themselves on the street. I can see Pway, S&T, Offtrack, Operations (so MOMs I guess) and interestingly Telecoms (though presumably not an organisational subdivision of Eastern telecoms)

E&P will typically have OLE section managers, and Plant & Distribution section managers.

There aren’t Delivery Units within Maintenance Delivery Units, at least not in an organisational sense.

Colchester was the Maintenance Delivery Unit, but it moved to Ipswich many years ago. What is now at Colchester is (I think) Colchester Track Section Manager and the Colchester S&T Section Manager.

Norwich has various sections that are part of the Ipswich MDU. Except Ops of course, that is for the Local Ops Managers who manage the MOMs and the various operational outposts out there (Trowse box and the three pure swingbridges)

 

[GraphitProjekt]

Usually there will only be one TME per Maintenance Delivery Unit, although occaisonally two.

Curious, As far as I can tell in the above data (unless lots of re-organisation has occurred): Sandwell & Dudley, Doncaster and Darlington are the only MDUs to have just one TME. The majority have 2 or 3 and a few have more, Lancashire & Cumbria MDU has 5?!

The delivery unit boundaries tend to stay broadly the same between each discipline

This is good to know thanks

The maintenance engineer boundaries can differ. In my DU one STME has only one S&T section. That section is covered by two main pway sections that fall under one TME but crosses into another pway area on one boundary and another DUs TME area on the other border.

Ah so there's lots of messiness!

* was it renamed at some point? I always thought it was West but your map has it as South.

I've seen both, the ORR doc says "South" and so I thought that sounded a little better than saying "Western West".

E&P will typically have OLE section managers, and Plant & Distribution section managers.

Interesting! I'd imagine P&D section areas can be quite large, for example East Mids, where there are only a handful of 25kV substations in Bedford MDU.
Is E&P also responsible for signalling power or does the department just not exist where areas don't have any electrification

There aren’t Delivery Units within Maintenance Delivery Units, at least not in an organisational sense.

Okay so is it better to conceptualise it as some DUs have an IMDM present and acts as the top level underneath the route

Colchester was the Maintenance Delivery Unit, but it moved to Ipswich many years ago. What is now at Colchester is (I think) Colchester Track Section Manager and the Colchester S&T Section Manager.

The sign facing he platforms has remained however! There is another building I can see on streetview called "Ipswich MDU: Colchester depot".

Norwich has various sections that are part of the Ipswich MDU. Except Ops of course, that is for the Local Ops Managers who manage the MOMs and the various operational outposts out there (Trowse box and the three pure swingbridges)

Surely apart from Track as I did see a specific Norwich TME mentioned in the dataset with a Norwich TSM and Lowestoft TSM?

 

[Bald Rick]

Curious, As far as I can tell in the above data (unless lots of re-organisation has occurred): Sandwell & Dudley, Doncaster and Darlington are the only MDUs to have just one TME. The majority have 2 or 3 and a few have more, Lancashire & Cumbria MDU has 5?!

Apologies, brainfart on my part.

Okay so is it better to conceptualise it as some DUs have an IMDM present and acts as the top level underneath the route

Every Maintenance Delivery Unit has an IMDM who is responsible for it.

 

[Elecman]

E&P Distribution are responsible for signalling Power supplies and of the 650 and 400 volt distribution cabling

 

[GraphitProjekt]

Every Maintenance Delivery Unit has an IMDM who is responsible for it.

Hmmmm? So Anglia (since we were mentioning it) has 3 MDUs and so 3 IMDMs: Romford, Tottenham, Ipswich.
Within Ipswich MDU there is a TME for Ipswich and another for Norwich. So what actually is Norwich known as? There are signs calling it a "Maintenance Delivery Unit", and others just saying "Norwich depot".
It's only because I've definitely seen many people throw around "DU" to mean offices/facilities which are not the top level MDU with the IMDM. Is this just a lazy use of terminology?

== Doublepost prevention - post automatically merged: 22 Jul 2026 ==

Something else I'd be interested to know is where the OLE maintenance depots are located, I've heard of few but mostly guess work.

For Anglia, I know there is Romford and Pitsea at least, Cheshunt possibly. (And Colchester for E&P)

For East Coast, I've heard of a Hornsey depot and also a Hitchin which seems like quite a dense coverage - maybe Hitchin strays into Anglia territory. Then I'd imagine there's one for each MDU: Peterborough has a training facility I think, Doncaster, Darlington, Newcastle. (Additionally, Alexandra Palace E&P)

East Midlands is just Bedford

North & East: Holbeck for Leeds MDU???

WCML S: Stonebridge Park (Euston MDU), Bletchley, and so I'd expect Stafford?

Central: no idea...

North West: Longsight? Surely there's more though

For Western there's actual information online for this so: East MDU has Westbourne Park and Reading, Central MDU has Swindon and Bristol.

Wales: Cardiff MDU has Newport, not sure regarding CVL maybe they share, maybe there's Taffs Well site

Scotland: Shields, Carstairs, Portobello. Perhaps another depot was put in for EGIP