mk1 COACHES - WHO IS CORRECT?

[vectislad]

The dimensional differences between Hornby and Bachmann MK1s has been well recognised for some time - particularly the difference in roof height. But this difference I have now discovered also applies to Mainline MK1 which blend naturally with Hornby but hit the same roof height problem when matched with Bachmann. So does anyone know which is the most accurate?

 

Jim Carter

[Pint of Adnams]

The dimensional differences between Hornby and Bachmann MK1s has been well recognised for some time - particularly the difference in roof height. But this difference I have now discovered also applies to Mainline MK1 which blend naturally with Hornby but hit the same roof height problem when matched with Bachmann. So does anyone know which is the most accurate?

 

Jim Carter

None might be correct...

 

Prototype Mk1 gangwayed coach - heights from top of rail

 

3' 5.5" to buffer centreline

4' 0 1/4" to underside of body panels

10' 6" to gutter

12' 4.5" to top of roof

12' 8.125" to top of vents

12' 9.5" overall height

 

Widths

 

8' 9" over gutters

9' 0" over body and stepboards

9' 3" overall (i.e. including door handles)

 

Dimensions vary for non-gangwayed and NPCS vehicles.

[adb968008]

Looks perspective i think Hornby has the better shape, it also fits the profile of the Replica / Mainline variants very well.

 

Thats my opinion.

 

When running them, if your looking at the moving, from 2ft away youd not notice the difference though. I run my Mainline / Replica FO / Restaurants interchangably with Hornby and Bachmann, but rebogieing / new couplings and metal wheels were a must, flush glazing sets them up real nice.

[Phil Bullock]

Looks perspective i think Hornby has the better shape, it also fits the profile of the Replica / Mainline variants very well.

 

Thats my opinion.

 

When running them, if your looking at the moving, from 2ft away youd not notice the difference though. I run my Mainline / Replica FO / Restaurants interchangably with Hornby and Bachmann, but rebogieing / new couplings and metal wheels were a must, flush glazing sets them up real nice.

 

What are you using for flush glazing in those? 

 

Cheers 

 

Phil

[adb968008]

What are you using for flush glazing in those?

 

Cheers

 

Phil

SE flushglaze but its a bit of a faff getting those small windows in ! Ive around 15 to do ( as i have a Replica Intercity white roof FO set too), started out doing the Restaurant (i have maroon / green / blue grey of these), which comes up good, but then started doing one side only for now on the IC white roof FO set.

Ive heard Replica sell flushglazing for their FOs? If so at Warley i may take a change of approach.

 

The Replica FO sits really good to the Hornby Mk1, if Replica re-run some new Restaurants i reckon the market would take them well, i should add the new bogies / couplings i added were Replicas also, R8264 for wheels, i bulk bought 200 wheelsets when Amazon were selling them at £6 a pack (of 10) a few months ago, but its amazing how fast you use them.

Edited November 4, 2018 by adb968008

[Phil Bullock]

Many thanks

 

Have done FO and RU likewise - and both have close coupling too, as you say they stand up well

 

The flushglaze can look a bit prismatic but like you I can live with it....

 

IIRC the Replica glazing includes the glazing bars which you would have to paint....

 

Phil

[adb968008]

Many thanks

 

Have done FO and RU likewise - and both have close coupling too, as you say they stand up well

 

The flushglaze can look a bit prismatic but like you I can live with it....

 

IIRC the Replica glazing includes the glazing bars which you would have to paint....

 

Phil

Ah, thanks for that, i assume therefore on the older ones you need to cut out the sidelights then as they are moulded as part of the body ?

[SRman]

SE flushglaze but its a bit of a faff getting those small windows in ! Ive around 15 to do ( as i have a Replica Intercity white roof FO set too), started out doing the Restaurant (i have maroon / green / blue grey of these), which comes up good, but then started doing one side only for now on the IC white roof FO set.

Ive heard Replica sell flushglazing for their FOs? If so at Warley i may take a change of approach.

 

The Replica FO sits really good to the Hornby Mk1, if Replica re-run some new Restaurants i reckon the market would take them well, i should add the new bogies / couplings i added were Replicas also, R8264 for wheels, i bulk bought 200 wheelsets when Amazon were selling them at £6 a pack (of 10) a few months ago, but its amazing how fast you use them.

I found that the small vent windows were a real pain to do, so ended up cheating a bit when I did further coaches: I used Krystal Klear (there are other similar PVA-based glazing liquids) for all of the small windows (i.e. the Krystal Klear was the glazing medium) and also to glue in the larger panes, as it dries clear so hides any accidental gaps.

 

As for Mainline coaches, the earlier products had main windows that were too small and the roof gutter line was a little too low. They did make a good basis for some Bulleid conversions using Comet brass sides though, as I was able to glue the tops of the sides to the gutters to produce a more characteristic profile for the Bulleid coaches.

Edited November 5, 2018 by SRman

[ThaneofFife]

None might be correct...

 

Prototype Mk1 gangwayed coach - heights from top of rail

 

3' 5.5" to buffer centreline

4' 0 1/4" to underside of body panels

10' 6" to gutter

12' 4.5" to top of roof

12' 8.125" to top of vents

12' 9.5" overall height

 

Widths

 

8' 9" over gutters

9' 0" over body and stepboards

9' 3" overall (i.e. including door handles)

 

Dimensions vary for non-gangwayed and NPCS vehicles.

 

Were the heights unaffected by the bogies/wheel diameters or were they all the same?  

[34theletterbetweenB&D]

The dimensions are nominal ex works, and will have had applicable tolerances. In service wheel tyres wore and were reprofiled, bearing crowns lost material to wear, and spring systems deformed, so you should expect variation in height. I would guess at the progressive loss of up to a couple of inches from nominal, until the minimum acceptable dimension the tolerance allowed at the buffing and coupling faces, and then replacement parts to restore to original condition. In 4mm model terms it's next to nothing.

 

Regarding the Bachmann mk1 as originally released, all the measurements I tried were pretty much bob on, except the roof height at 50mm above rail top. That was caused by the socking great over-representations of the (flush as constructed) roof panel welds. Once the weld representations were removed all was well, and Bachmann eventually got around to fixing this which was very welcome. The real asset of this range for the lazy modeller who simply wants trains for his locos to operate on the layout is that they present the largest selection of types in uniform quality, which nicely replicates the appearance BR were after. And (ER relevant) with Gresley and Thompson stock intermixed in a formation, they are visibly different just as it was in reality. More than 'good enough'.

[JSpencer]

A thing to note is that Hornby have 2 lots of Mk 1s.

 

1st there is the old Triang-Hornby era mark 1s. These were given flush glazing in the late 90s but they sit far too high compared with the prototype and everyone else (except maybe Lima Mk1s). They were made until quite recently and most doubtless appear on ebay and other SH items (look at the couplings, if they are big tension locks then that is them).

 

Then they did their newly tooled current range Mk1s. IMHO they work perfectly well with the modern Bachmann super detailed types and the older Replica (some ex-Mainline) types.

 

My green BR/SR rake uses mostly Bachmann and one Hornby coach and can be strengthened with the Replica coaches as I need operationally.

 

My blue/grey is mostly the recent Hornby items with one Bachmann resto.

[Wickham Green]

None might be correct...

 

Prototype Mk1 gangwayed coach - heights from top of rail

 

3' 5.5" to buffer centreline

4' 0 1/4" to underside of body panels

10' 6" to gutter

12' 4.5" to top of roof

12' 8.125" to top of vents

12' 9.5" overall height

 

Widths

 

8' 9" over gutters

9' 0" over body and stepboards

9' 3" overall (i.e. including door handles)

 

Dimensions vary for non-gangwayed and NPCS vehicles.

None are correct ....... you forgot Track Gauge : 4’8½’’

[Pint of Adnams]

None are correct ....... you forgot Track Gauge : 4’8½’’

 

There's always one, isn't there 

[DCB]

All our Triang and Triang based Hornby Mk1s have had their ride height reduced by cutting away the tower which supports the bogies.  The Triang stock used a buffer height 1mm higher than scale to accommodate the tension lock coupling right across the range locos included.   I cut some with a hacksaw blade without actually removing the bogies. They all have recent replacement Hornby metal wheels and painted interiors which helps the appearance.

Generally with the ride height sorted the Hornby buffers and cant rails line up with Bachmann, Mainline etc MK1s. However they always look more convincing to me in sets by one manufacturer than mixed up.   

Lima is a bit more tricky.  The lack of relief around the windows is really noticeable coupled to Hornby or Bachmann but they run beautifully so I keep them in close coupled sets as far as possible. 

I would suggest you pick a cant rail or base of the sides height and make up a template and adjust your stock to suit.   A sfull Mk1 et with cant rails all in line and the back of a GWR Collett 4000 gallon tender in line with the cant rails looks right whereas a set with one just coach low looks very odd. (like the Mk2 sets with Mk 1 restaurant  cars did!)

I find it much easier to make up a jig than to measure these dimensions

[Wickham Green]

All our Triang and Triang based Hornby Mk1s have had their ride height reduced by cutting away the tower which supports the bogies.  The Triang stock used a buffer height 1mm higher than scale to accommodate the tension lock coupling right across the range locos included.   I cut some with a hacksaw blade without actually removing the bogies. They all have recent replacement Hornby metal wheels and painted interiors which helps the appearance.

Generally with the ride height sorted the Hornby buffers and cant rails line up with Bachmann, Mainline etc MK1s. However they always look more convincing to me in sets by one manufacturer than mixed up.   

Lima is a bit more tricky.  The lack of relief around the windows is really noticeable coupled to Hornby or Bachmann but they run beautifully so I keep them in close coupled sets as far as possible. 

I would suggest you pick a cant rail or base of the sides height and make up a template and adjust your stock to suit.   A sfull Mk1 et with cant rails all in line and the back of a GWR Collett 4000 gallon tender in line with the cant rails looks right whereas a set with one just coach low looks very odd. (like the Mk2 sets with Mk 1 restaurant  cars did!)

I find it much easier to make up a jig than to measure these dimensions

Not quite sure what you mean about the 'lack of relief around the windows' on Lima Mk 1s ........ in the - pre-preservation-era - days when Mk 1s were regularly hauled behind GWR Collett 4000 gallon tenders, the majority would not have have had aluminium-framed windows.

[The Johnster]

The coaches 'settled' a bit under the combined load of up to 64 passengers as well, so we are splitting hairs here.  I find roof line variation on what should be a train of standard vehicles very noticeable, though, and it is absolutely vital that the couplings are the same height at the bar.  

 

My view is that you won't go far wrong if you run rakes made up of coaches from the same source; it is only when you mix them within the rakes that you will have visual and possibly operational problems.

 

There are 3 variations of 'relief' surrounding windows, none, the raised beading of aluminium framed windows, and the later beading an inch or so wide which characterised blue/grey stock.  These are very noticeable if you look along the length of the train against the light, but only brand new rakes on prestige trains would be the same throughout in service; the general run of mk1 work, especially after mk2s began to cascade them and the last big 4 coaches were withdrawn, was mix and match.  At Canton, and most similar places, in the 70s we had 'A' stock, with B4 or Commonwealth pattern bogies and capable of 100mph running, and 'B' stock, still on 90mph B1 bogies and less likely to have been internally refurbished; the latter were mostly used as excursion and relief stock.  They generally looked a little shabbier.

[Gibbo675]

Were the heights unaffected by the bogies/wheel diameters or were they all the same?  

Hi Thane of Fife,

 

The ride height of all railway vehicles is set via measuring buffer heights and is 41.5" plus 0.5" and minus 1.5". Tall steam locomotive are generally checked over their extremities just to make sure they are within kinetic envelope, however this would not greatly affect coaching stock as they are usually approximately 5" lower than maximum gauge which is 13' 1".

 

Tyre thickness are 3" for new tyres with 1.5" final turning size, wheel sets are measured to within .010" on diameter across an axle and wheel sets must be within .25" of each other within a bogie frame.

Ride heights are altered using circular shim packing's of varying thickness between the bolster and the underframe pivot to account for variance of tyre thickness.

Spring weights altered by the use of screw adjusters and shims depending on bogie type to set axle box and bolster suspension gaps. It is acceptable to have new tyres on one bogie and final turning thickness tyres on the other bogie so long as buffer heights are within limits.

 

Depending upon the service to which any type of vehicle is to be put will depend upon the ride height that it is set to when shopped. For example the vehicles with the greatest variance between fully loaded and tare weights are steam locomotive tenders for they run low when full and high when empty, even more so than high capacity goods wagons both of fixed wheelbase and bogie types. support coaches are usually set about .5" high tare and should they be fully loaded they will then sit approximately .5" low of the 41.5" compared to Steam locomotive tenders that will take up the full 2" of tolerance between fully loaded and empty.

 

From memory so I may be slightly inaccurate here, total axle box travel is about 3" and bolster travel about 1.5" so in the unlikely event that two vehicles coupled together with one topped out on suspension set to top limit buffer height and the other bottomed out on suspension set to bottom limit buffer height will still have 6" of buffer face engagement if fitted with 16" diameter buffer heads.

 

Gibbo.

Edited November 6, 2018 by Gibbo675

[Bob Reid]

Gibbo, is this some kind of new tolerance + or - 1 1/2" on the buffer height?  The "nominal" height of 3'-5 1/2 has Long been a standard on for example Mk1 & Mk2 stock and set at tare weight.

 

[edit to add] Are these from a preservation standard? The reason I ask is there's a few discrepancies with the sizing or are you mixing up loco's and rolling stock and I'm interested to know to what standard these are taken from.

Edited November 5, 2018 by Bob Reid

[Bob Reid]

To expand on what I was saying earlier...

 

The "nominal" buffer height for Mk1 & Mk2 stock (on straight and level track) is 3'-5 1/2" Centre of the buffer to Rail Level.  This dimension, following overhaul had a tolerance for setting of +1/2" i.e. 3-6" Maximum.  This was set on straight and level track at tare weight - i.e. without passengers, but with full water tanks.

 

Between overhauls there was a monthly exam requirement at depots to ensure that they remained or were maintained within 3’-5 1/4” and 3’-6” I.e. -1/4”/+1/2” irrespective of wear or the wheel/tyre dimensions, again on a reasonably straight and level track.  This tolerance was positively essential with stock fitted with Pullman type gangways to keep the gangway tread plates level between adjacent vehicles (or at least within 3/4” of each other).

 

the overall dimensions kindly given by Pint of Adnams are based on the nominal ex-works buffer height of 3'-5 1/2" (1054mm) so given the accepted tolerance the overall height (to the top of the roof panels) of 12'-4 1/2"  could vary between 12’-4 1/4” and 12’-5” - at 4mm scale and in metric, anything between 49.4mm and 49.6mm is quite spot on.

 

Clearly the state of the track, dynamic movement and loading  of the vehicles varied these heights in traffic - especially when running.

Edited November 6, 2018 by Bob Reid

[Gibbo675]

Gibbo, is this some kind of new tolerance + or - 1 1/2" on the buffer height?  The "nominal" height of 3'-5 1/2 has Long been a standard on for example Mk1 & Mk2 stock and set at tare weight.

 

[edit to add] Are these from a preservation standard? The reason I ask is there's a few discrepancies with the sizing or are you mixing up loco's and rolling stock and I'm interested to know to what standard these are taken from.

Hi Bob,

 

Thanks for pointing out my mistake I added an inch to the upward tolerance, your quoting of 3'4"- 3'6" is indeed correct.

 

Can't remember the number of the group standard document as I packed it all in ten years ago when both the politics and proclivities at Riley and Son's got to be a bit too much to put up with.

 

The three inches of total travel was from 34067's tender despite the springs being to diagram and of the correct spring rate as tested. It was quite a juggle getting getting the buffer heights to look right with out the guard irons being either too high or scraping the rail head when running fully laden. Our Stanier and BR Std tenders very nearly took up the full travel mainly because we had increased the water capacity by 750 gallons which is an extra 3.5 tons and mainly over the back end of the wheel base.

 

Support coaches were very often set 0.5" high at tare to allow for all the spares, bags of coal and associated clutter, we had extra tanks for the shower in the opposite end to the brake to assist in balancing things out, also they ran on Commonwealths and if we had performed a spring change then the rubbers within the shim packing's under the primaries would settle slightly but not by much. They were always rechecked once filled with clutter !

 

I also worked upon freight wagon inspection and reporting for RESCO shortly before their demise and they do very quite some depending upon loadings although again within the 3'4"-3'6" range.

 

Good job I only play with toy trains these days !

 

Gibbo.

[Theakerr]

Re the SE Finecast window installation, I found that the draft angle on the Mainline coaches is from the outside, but is from the inside on the Finecast.  Therefore filing a draft angle flowing to the coach inside greatly helps installation of the Finecast 'windows' from the inside and eliminates some of the compression distortion effects.

[Bob Reid]

Thanks Gibbo. Coincidentally, back in the day, I was doing the annual exams on ScR based private coaching stock for registration for mainline running - at least whist I still worked for the DM&EE.

[E3109]

Just to add, and I know the pivot centres are wrong on the Tri-ang derived coaches but if you can live with that discrepancy an adjustment to the ride height is easy enough, simply file out the plastic on the bogie around the pivot, if you take out too much then shimming should be easy enough.

I haven't actually done this by the way, but worth considering maybe.

I'm more concerned with side bearers really, nowt worse than a rocking coach!

[Covkid]

Interesting comments.  I recently took advantage of the Kernow deal of D845 and four choc n cream Mk1s for a penny less than £200. 

I decided to augment the Bachmann Mk1s with an additional SK, FK and maroon Restaurant. The SK was a Hornby railroad item whilst the other two are Bachmann.  I feel the shapes are very very similar and the colours will blend in with a bit of roof and bogie grime. The only standout difference which draws the eye is the toilet window glass on the SK which is white rather than the more realistic Bachmann colour.

 

The rake is only a "layout" rake anyway so I am a happy bunny. 

[Ray M]

The 3rd one here is running a little high

on the KWVR in 2014 (click for bigger pic)