TOPS Number Categories

[Scotrail344Lad]

Hello all.
This might not be 100% right but this is what I expect the TOPS system to be like? Is there any sort of official document etc?
Please correct me if wrong.

X = Placeholder for another number.

Class XX
E.g. Class 43, Class 56, Class 08
Locomotives

Diesels are class 00 to 70, 70 to 79 was 3rd rail locos, 80-97 electrics (recently including bimodes), 98 steam/heritage locos. Everything higher has been allocated to GBRf For Their New Fleet.

Class 1XX
E.g. Class 156, Class 104, Class 158
Diesel Multiple Units

Class 2XX
E.g. Class 220, Class 222 & Class 230
Diesel Electric Multiple Units

Class 3XX
E.g. Class 320, Class 315, Class 385
Electric Multiple Units

Class 4XX
E.g. Class 458, Class 455, Class 450
Third Rail EMU's (Southern Region)

Class 5XX
E.g. Class 507, Class 508 & Class 555
Third Rail EMU's (Elsewhere (Mersey/Tyne & Wear))

Class 6XX
E.g. Class 614 & 600 (Both Experimental)
Hydrodgen Trains

Class 7XX
E.g. Class 700, Class 701, Class 730
Dual Voltage Or Bi-Mode (As Said In Post #2)

Class 8XX
E.g. Class 800, Class 805, Class 810
Modern Trains Capable Of More Than 120MPH

Not going to add anymore as not much point - not that there really is more.

So! Please correct me and let me know the details

 

[zwk500]

The classes have changed a few times over the years, hence why you get 3xx intercity trains that would nowadays be 8xx.

There are some technical differences in the RSSB standard that governs the TOPS allocation but the thrust of it is there (e.g. 8xx being 'faster than 120mph' rather than Intercity, IIRC).
0xx doesnt exist, its 'xx' and covers all locos. Diesels are class 00 to 70, 70 to 79 was 3rd rail locos, 80-97 electrics (recently including bimodes), 98 steam/heritage locos and 99 was ships but has since been allocated to GBRF's new fleet (despite 94-96 being free, and several of the earlier.classes being only heritage survivors)
7xx Is dual voltage or bi-mode.

 

[Scotrail344Lad]

Thanks

Edit - Updated Post #1

 

[43096]

7xx Is dual voltage or bi-mode.

It isn't. It's effectively an overspill from other classes and is a right mixture.
701 is DC only
707 is DC only
720 is AC only
730 is AC only
745 is AC only

Let's be honest, the current system is an utter mess with no control and operators seemingly able to pick whatever class number they want.

 

[Gloster]

Wasn’t 97 XXX allocated to BR Departmental locos and also to other authorities’ motive-power that could appear on the national network?

 

[norbitonflyer]

89xxx is non-steam heritage locomotives, but most usually carry their original numbers unless they have been duplicated by something newer.

Technically, a 73 is a bimode.

Most modern electric units (whether 3xx, 4xx or 7xx), are capable of conversion from ac to dc or vice versa, although I don't think 7xx is exclusively for such.
Bimodes are generally 750-799

 

[Scotrail344Lad]

Thanks

 

[tfw756rider]

Wasn’t 97 XXX allocated to BR Departmental locos and also to other authorities motive-power that could appear on the national network?

Yes, there are currently 3 operational Network Rail yellow Class 97/3 English Electric Type 3 (normally Class 37) locomotives with ETCS signalling equipment for use on the Cambrian railway (Shrewsbury-Aberystwyth and Machynlleth-Pwllheli) - 97302, 97303 and 97304, and they're Diesel-electric.

So "80-97 electrics" should read "80-96 electrics" and 97 is departmental locomotives @zwk500.

As for 7xx, I believe it's simply electric multiple units, but an additional number range than can be used instead of 3xx.

I believe 6xx was meant to be an additional number range for diesel multiple units, but was only used for a hydrogen unit for some reason.

The 376s have only ever been used on third rail, but I remember from a previous discussion that they "have enough provision for conversion to overhead" to not be 4xx.

== Doublepost prevention - post automatically merged: 4 Apr 2026 ==

89xxx is non-steam heritage locomotives

Why is the 1986 prototype electric locomotive for the East and West Coast Main Lines a Class 89?

 

[43096]

Why is the 1986 prototype electric locomotive for the East and West Coast Main Lines a Class 89?

Because Class 89 was the next in the sequence, and pre-dated the use of 89xxx for heritage diesel and electric locos.

 

[norbitonflyer]

Why is the 1986 prototype electric locomotive for the East and West Coast Main Lines a Class 89?

The 89 classification was the next one after 87 and the proposed (but never built) 88 - not to be confused with the more recent bimode class 88. The classification has now been re-purposed for use in NR databases for preserved "modern" traction. Like the class 98 steam numbers, they take the format 89xyy where x is the power type and yy is (usually) the last two digits of the cabside number - so D345 (40145), being a Type 4, would be registered as 89445. (They of course use the diesel power classification (1-5) rather than the steam one (1-9).

89001 is, of course, itself preserved now, so already fits in the right range.

 

[Supercoss]

As with all sticky digits, a rail industry standard exists -

 

[Scotrail344Lad]

As with all sticky digits, a rail industry standard exists -
View attachment 201681

Thanks, Very informative

 

[Jim Jehosofat]

When I was a boy class 99 were BR ships

 

[Supercoss]

And 4th column over for locomotives

 

[Western Sunset]

Don't forget the Manchester - Glossop 1500v DC overhead units were classed as 506.

 

[norbitonflyer]

It isn't. It's effectively an overspill from other classes and is a right mixture.
701 is DC only
707 is DC only
720 is AC only
730 is AC only
745 is AC only

Let's be honest, the current system is an utter mess with no control and operators seemingly able to pick whatever class number they want.

701 and 707 can be conveerted to AC, and some examples were tested in that mode

== Doublepost prevention - post automatically merged: 4 Apr 2026 ==

Don't forget the Manchester - Glossop 1500v DC overhead units were classed as 506.

5xx was all DC units outside the Southern
501 LMR London area units (3rd rail - originally 4th rail)
502/503 mersey rail (3rd rail)
504 Bury line (3rd rail side contact)
505/506/555 Manchester- Altrincham/Glossop, Tyne & Wear (overhead)

 

[Wyrleybart]

When I was a boy class 99 were BR ships

And me !! I think it was those with rails welded to the decks and technically needed to "haul" the wagons across the channel.
I had 99006 Speedlink Vanguard Harwich - Hoek and I also think Vortigern 99007 and 99012 Chartres

== Doublepost prevention - post automatically merged: 4 Apr 2026 ==

It isn't. It's effectively an overspill from other classes and is a right mixture.
701 is DC only
707 is DC only
720 is AC only
730 is AC only
745 is AC only

Let's be honest, the current system is an utter mess with no control and operators seemingly able to pick whatever class number they want.

And the 710s which I think are variously AC and AC/DC

 

[norbitonflyer]

And me !! I think it was those with rails welded to the decks and technically needed to "haul" the wagons across the channel.
I had 99006 Speedlink Vanguard Harwich - Hoek and I also think Vortigern 99007 and 99012 Chartres

== Doublepost prevention - post automatically merged: 4 Apr 2026 ==


And the 710s which I think are variously AC and AC/DC

And 717s of course

 

[SECR 65]

So are Electrostars which are 3rd rail only (e.g. 377 /1 /2 /3 /4) not a 4XX because they can be converted to overhead line operation easily?

And what TOPS numbers do mk1 or other heritage carriges on the mainline get? I had a feeling it was 99xxx but I may be wrong.

 

[norbitonflyer]

So are Electrostars which are 3rd rail only (e.g. 377 /1 /2 /3 /4) not a 4XX because they can be converted to overhead line operation easily?

Probably - but the 450s and 458s could be too. Indeed some of the original order of 450s ended up as 350s.

 

[Falcon1200]

70 to 79 was 3rd rail locos

70 to 79 was 3rd rail locos

Would 70-79 not have been DC powered electrics perhaps, given that Classes 76 and 77 (the Woodhead route locos) were not third rail?!!

 

[Helvellyn]

• 70-71 third rail DC electric locos
• 72-75 Electro-Diesel locos (third rail DC electric)
  • 72 was originally assigned to the 73/0 locos
  • 75 was reserved for a super Electro-Diesel (never built)
• 76-79 overhead DC electric locos

 

[wickham]

It isn't. It's effectively an overspill from other classes and is a right mixture.
701 is DC only
707 is DC only
720 is AC only
730 is AC only
745 is AC only

Let's be honest, the current system is an utter mess with no control and operators seemingly able to pick whatever class number they want.

Despite what has been said above, I beleive that the 7xx series are for "walk through" design units (ie: no end doors between cars and wide connections): Class 345 should be added to this list, but was designated before the new policy regarding "walk through" was decided.

 

[Peter Mugridge]

So are Electrostars which are 3rd rail only (e.g. 377 /1 /2 /3 /4) not a 4XX because they can be converted to overhead line operation easily?

377/2 are dual voltage, as are 377/7 ( but 377/6 are not - and yes, all 375s. 377s are capable of easy conversion ).

 

[norbitonflyer]

Despite what has been said above, I beleive that the 7xx series are for "walk through" design units (ie: no end doors between cars and wide connections): Class 345 should be added to this list, but was designated before the new policy regarding "walk through" was decided.

I don't think 7xx is dedicated exclusively to "walk-through" - it is just that most units (I think class 397 and the 8xx units are the only exceptions) built since the 7xx block was allocated to EMUs have been of that type. Classes 345, 378, 398 and 399 are all walk-through. The 397 is in a 39x group, with the Pendolinos and Javelins

 

[Merle Haggard]

When I was a boy class 99 were BR ships

I'm not sure if all BR ships were class 99 but the train ferries were, so that consists could be generated.

 

[swt_passenger]

Despite what has been said above, I beleive that the 7xx series are for "walk through" design units (ie: no end doors between cars and wide connections): Class 345 should be added to this list, but was designated before the new policy regarding "walk through" was decided.

I reckon it’s nothing to do with whether they were walkthrough or fixed formation. There was a supposition started by a former member here who insisted for ages 7xx was a special class just for Thameslink because they were fixed formation. When the rail group standard about TOPS classes was amended to introduce 7xx it was clear they were (at that time) simply class 3xx overspill, ie AC or Dual voltage EMU.

Then the 700-799 section has since been split at the 50 point, resulting in 777 being in the wrong place.

== Doublepost prevention - post automatically merged: 5 Apr 2026 ==

Probably - but the 450s and 458s could be too. Indeed some of the original order of 450s ended up as 350s.

This has come up a few times and the conclusion was that every relatively modern EMU class including the 444, 450 and 458 has been built as dual voltage capable so there’s no logical reason they shouldn’t have been 3xx as well. But it seems theres a lot of personal preference or tradition about choosing classes, it was possibly less about the engineering at the time.

 

[Falcon1200]

I'm not sure if all BR ships were class 99 but the train ferries were, so that consists could be generated.

Only the train ferries would ever need to be reportable to TOPS, though?

 

[Gloster]

It was only the train-ferries that had numbers on TOPS as they were the only ships that conveyed wagons of which the destination, status, etc. needed to be recorded. For all other ships TOPS’s interest ceased at the buffer stops.

 

[pokemonsuper9]

Class 2XX
E.g. Class 220, Class 222 & Class 230
Diesel Electric Multiple Units

Worth noting that there are 3 different types of Class 230
The LNWR ones (purely Diesel)
The TfW ones (Diesel/battery similar to a hybrid car)
The GWR one (purely battery).

I'm not really sure why the TfW ones and GWR ones are Class 230 when they're not purely diesel.