Powering a Bratchell EMU

[Martin_R]

Having recently acquired a Bratchell class 321 EMU I had to find a way to power it. Checking with Bratchell the recommended method is to use a Black Beetle with 12mm disc wheels on a 35.5mm wheelbase for the P7-4 power bogie on the PMSO car. Now I’m not a great fan of Black Beetles on the basis of high cost and level of performance so I set out to find a cost effective alternative method of making it run reliably. A Black Beetle power bogie plus dummy would set me back the best part of £80 and 2 power bogies around £110 so I had a budget to work to.

 

In the past I have motorised a Bratchell Class 150 using much modified Bachmann Class 25 chassis parts – a lot of work and it intrudes too much into the body. I have also used Heljan Class 17 chassis parts to power other DMU’s, much better but my stock of chassis parts has now dried up. Using this type of chassis can also give you a DCC option should you want it

 

I had one of the Replica Railways powered chassis with 12mm wheels with the original intention to power a DC kits class 128 (now overtaken by the Heljan offering) so out came the callipers and yes it will fit! The bogie centres are near enough spot on but the bogie wheelbase at 34mm was 1.5mm too short. The overall chassis length was fine as was the width if the moulded step boards were removed from the Replica chassis surround.

 

Fitting the chassis to the body.

 

The Replica chassis is a totally self contained twin motored drive unit with DCC connections onboard. The chassis has a removable chassis surround which is used to mount under frame detail. At each end of the Replica chassis there is a cab back plate that I used as the basis for fixing the chassis unit securely to the EMU body.

 

The chassis surround was removed and the moulded step boards are carefully cut from the Replica chassis surround to give the correct chassis width to fit inside the Bratchell body.

 

The back plates are reversed but reversing the end plates will then make the chassis too long to fit between the coach ends. The non-pantograph end of the body needs a notch cut in it to allow a modified and narrowed back plate to fit through. The back plates are modified to match the roof profile, flat top at the pantograph end and a curved top made from plasticard is added to the narrowed back plate at the other end.

 

01 Chassis End Plate

02 Reversed Chassis End Plate

03 Class 321 Pantograph End

04 Class 321 non Pantograph End

05 Modified Chassis End Plate

 

The moulded body fixings on the chassis surround need to locate against the underside of the window mouldings to give the correct ride height and the 4 end fixings need notching to clear the Bratchell moulding pips at each end – this gives a longitudinal location.

 

The chassis should sit inside the body by 2mm to give the correct ride height. Once happy with the fit of the chassis the end plates can be fixed to the body. Remove the chassis surround and fit into the body with end plates ensuring it is square and has an equal 2mm inset along both sides. I used a 5 minute epoxy to fix the end plates to the inner roof of the body. Once set remove the chassis surround and re-assemble chassis and re-fit to body.

 

06 Step Board Removed

07 Notched Body Locator

08 Frame Location Pantograph End

09 Frame Located Non Pantograph End

10 End Plate Fixed Pantograph End

11 End Plate Fixed Non Pantograph End

 

The original Bratchell chassis details are used by cutting off the ends leaving just the centre section with the under frame equipment on. The raised ribs along the inside edge need to be carefully removed making sure to retain the original raised location rib which will hold the chassis detail in place inside the body.

 

12 Bratchell Chassis

13 Chassis Centre Section Detail

14 Chassis Inner Ribs

15 Chassis Ribs Removed

16 Location Rib Retained

17 Chassis Detail Fitted Into Body

 

Modifying the Replica bogie side frames and P7-4 Bogie detail.

 

Here I had a choice, leave the Bratchell frames as they are and ignoring the length mismatch or shorten them. I decided to modify the Bratchell frames as the axle box to wheel centre misalignment was visibly obvious.

 

The Replica bogie side frames are prised off the bogies and profiled to match the Bratchell P7-4 frame shape.

 

The Bratchell bogie frames are cut into 3 sections, trimmed to size and fixed to the Replica bogie side frames ensuring the axle boxes and wheel centres line up.

 

I refitted the NEM coupling boxes to the bogies and also fitted NEM coupling boxes to the bogies on the other vehicles. My choice of couplings has changed recently following the article on magnetic couplings in Traction Magazine back last year. Magnetic couplings in various configurations are now my coupling of choice for DMU/EMU units (coaches and wagons rakes too) where electrical through connections are not required.

 

18 Replica Bogie Frames Original & Modified

19 P7-4 Bogie Frame

20 P7-4 Frame as Supplied

21 Modifying P7-4 Frame

22 Assembled P7-4 Modified Frame

23 P7-4 Modified Frame

Edited April 22, 2013 by Martin_R

[SRman]

I powered my Bratchell class 455 with the Replica motor chassis and am very happy with the running qualities. I have yet to fit all the underframe bits and pieces, though!

 

I used another Replica chassis in a DC Kits 4 EPB, with similar very good results.

[Xerces Fobe2]

I powered my Bratchell class 455 with the Replica motor chassis and am very happy with the running qualities. I have yet to fit all the underframe bits and pieces, though!

 

I used another Replica chassis in a DC Kits 4 EPB, with similar very good results.

 

I have used Replica chassis's in DMU & EMU's and they are superb.

 

XF

[SRman]

I have plans for a class 319 when Bratchell produce the next issue and I will certainly go for another Replica chassis. 

 

I should have said that I also followed a very similar procedure to what Martin did with his motor bogie side frames. The Replica chassis dummy frames lend themselves nicely to reinforcing the joints.

Edited April 23, 2013 by SRman

[sub39h]

Slightly off the beaten track but I was wondering if a Bachmann Class 150 would be suitable to use to motorise a Class 319? Are the dimensions correct? I thought this would be a good way of sourcing a DCC ready chassis and some lights for less than the cost of a Replica chassis.

 

The intention would be to do what Jim S-W has done an cut down the metal block so it is not too visible.

 

If the dimensions are correct, how would one go about attaching the bodyshell to the chassis? And would you just remove the 150 under frame detailing and fit the 319 detailing or is it more complicated than that?

 

TIA

[Scottish Modeller]

Hi Sub,

 

I have this ongoing at the moment - it's not a straight fit.

 

I have removed all the underframe details off the CL150 chassis and will be attaching the detail to them once I have made them fit together!

 

I will be trying to make the body and chassis a tight fit so that they don't need any fastening together.

 

A work in progress!

 

A work in parts - certainly!

 

Thanks

[sub39h]

A bit of googling and reading through the archive has come up with another member who used a Class 170 instead. Would this be a better unit to use? There is some word of the 150 being a little slow for a 319 at full scale speed but surely a 170 would be better in this respect? Is there any way of gearing the 150 bogie towers to improve the top speed?

Edited December 28, 2013 by sub39h

[SRman]

The 150 should be the right length for the class 317/318/319/320/321 electrics whereas the 170 chassis will need to be shortened and modified more heavily to fit. Bachmann's 150s do have that horrible huge metal block, though. I'm not sure about regearing - in theory, other bogie drive units should fit but I know of no one who has tried this.

The Replica chassis fit very well and do not cover any windows but require some low-relief seats to complete the illusion of an interior being fitted. Top speed is reasonable.

My 319 in NSE livery should be arriving any day now. I have a Replica chassis and Sommerfeldt pantograph sitting awaiting its arrival.

Edited December 30, 2013 by SRman

[sub39h]

The plan was to cut down most of the metal block and hide the remainder behind the toilet so it's only minimally visible. Considering 150s are available for £53 from eHattons it would be quite a bit cheaper than the Replica chassis once you factor all the spares you get left over the flog, not to mention being slightly more accurate in terms of bogie size and wheelbase.

 

I know for some Bachmann models you can change the worm gear to improve the top speed but I don't know if this would work for the 150 and if so which worm gear would be most appropriate.

 

May I ask which pantograph would be mos suitable?

Edited December 29, 2013 by sub39h

[SRman]

319/0s used a Faively style pantograph, for which I bought a Sommerfeldt one. The 319 Bratchell are offering (or about to) is a 319/1 which should use the Brecknell-Willis high speed pantograph. I couldn't find any of those in the usual places and the Hornby offerings are crude (the earlier ones as on my class 92 are rather chunky, wheres the later plastic ones are very fine but tend to be permanently bent). 

Then I bought a Bachmann class 350/1 to convert to a class 450 and lo and behold, there was my pantograph!

 

Edited to correct a couple of typos and the spelling of "Sommerfeldt".

Edited December 29, 2013 by SRman

[sub39h]

Haha perfect! I did invest in a set of the Hornby 92 pantographs as a temporary measure but they are just so fragile!

[SRman]

319 174 in NSE livery has arrived in kit form today. I have already assembled the body shell with windows (pre-fitted to make things easier) of the pantograph motor second which will also have the Replica chassis fitted. 

 

One slight adjustment was required for each side (additional to the supplied instructions): there are two moulded spigots on  each side at cantrail level on the insides, which need the spigot at the pantograph roof well end to be filed down slightly so as not to force the sides outwards as they foul the pantograph well sides.

 

Other than that, construction should be just as straightforward as the 455 (see my workbench blog if interested). In fact, becuse there are no jumper cables or handrails to add to the front ends, this should be easier.

Like the 455, I intend to drill out the lights and insert LEDs.

Edited December 30, 2013 by SRman

[SRman]

I have glazed and assembled all of the body shells and slipped the motorised chassis into the PMS coach (that's Pantograph Motor Second!). I still need to remove the moulded on footboards but I'll leave that until I am ready to adjust the height it sits at.

Now here's a question: does anyone have a good photograph of the pantograph well, please? I will need to recreate the insulator and bus bar runs as well as mount the panto in the right place.

 

Here are a couple of photos of the first bit of my progress.

 

 

Edited December 30, 2013 by SRman

[dasatcopthorne]

 

Now here's a question: does anyone have a good photograph of the pantograph well, please? I will need to recreate the insulator and bus bar runs as well as mount the panto in the right place.

 

 

 

 

 

 

Originally sent a message to your Blog on this but couldn't upload an image.

 

This is all I can find at the moment although I know I have more somewhere.

 

Dave

 

[dasatcopthorne]

Found them.

 

Hope they help

 

Cheers

 

Dave

 

& HNY!!

 

 

 

 

[SRman]

Dave, those are perfect! I couldn't ask for better.

 

Many thanks for posting those photos.

 

[Callander - ScotRail OO Gauge]

In the process of making an SPT Carmine & Cream Class 320, so using an RR chassis, I bought the wrong one last time!!!

[Northern323]

The replica models everyone speaks of in here seems to be the thing for putting in these bratchell model's. However this is part of the industry I am very much unfamiliar with. Does anyone have a link to where i can buy these replica chassis?  Was looking into a 319 in NSE but i have had cold feet looking at the additional work required to get them charged and moving.

[uax6]

Google produced this:

http://www.replicarailways.co.uk/menusep4/menuchass

 

Andy G