Considering the wheels for the City I could not find a supplier of GWR 6' 8" plain drivers, I could buy crank boss ones and cut out crank pin area but by the time you pay for a set of drivers and then rework them I thought it just as easy to make them and save a few quid for other items required.
This the test wheel, and I am quite pleased with it!
Mike
(https://i.ibb.co/TMw6fsR/P1090837.jpg) (https://ibb.co/TMw6fsR)
Very nice Mike. So that is CNC milled from solid ... aluminium?
Mike
Mike
Yes 1/4" thick ali with a 3mm end mill so you have a slow feed as ali is very sticky with small cutters, lots of suds!
I will have to order in some 4"dia BMS for the tyres, if I cut out the centres they should be big enough for the tender tyres?
Mike
Researching details on the City I found a very nice image of an original build, and an interesting comparison with the rebuilt version.
I prefer the original less busy, cleaner lines, and no top feed.
Mike
(https://i.ibb.co/qdGGX5v/IMG-20190505-0001.jpg) (https://ibb.co/qdGGX5v)
(https://i.ibb.co/9TdBQ1Q/3705.jpg) (https://ibb.co/9TdBQ1Q)
Advice sought regarding powering the City, I have a Mabuchi motor rated at 6-18v and am considering using a lead acid battery which will fit well in the tender and I would think will have more power than NiCad's. What amp range would this kind of motor pull under load?
That way I can add specific weight to the loco if needed i.e. front or back.
Thanks
Mike
I have not used lead acid cells in a model loco but Ralph is keen on SLAs and will no doubt give some advice.
I use Ni-MH cell packs rated at 2.3Ah which power either Buehler or Mabuchi motors with a 24V max. rating. I find that a 16.8V nominal pack (which fully charges to around 19V) will run for at least 2 hours with a reasonable load in tow, so the average current drawn would be around 1A.
I now fuse my locos 5A and have yet to blow a fuse.
On the advice of Brian Jones (supplier of Mac 5 ESC), I fitted my first-built G3 loco (LNER/GC N5 0-6-2T) with a thermal cutout rated at 1.6A and that has only once tripped, when the loco stalled.
Photos of the "guts" of Calcutta's tender below : Mtroniks Viper Loco 10 HV esc and "MyLocoSound" card included.
Regards,
John
Quote from: 753 on May 11 2019 10:03
Advice sought regarding powering the City, I have a Mabuchi motor rated at 6-18v and am considering using a lead acid battery which will fit well in the tender and I would think will have more power than NiCad's. What amp range would this kind of motor pull under load?
That way I can add specific weight to the loco if needed i.e. front or back.
Thanks
Mike
Mike, look at the Mabuchi website which will tell you certain performance data for each type of motor. Beyond these basics I find Mabuchi a pain in the neck, as they seem very secretive and selective about who is permitted to register on their site to see further info! Hardly a good business model... I'm still awaiting "approval" after several days! Moan over, I support the use of sealed lead-acid (SLA) batteries, but partly because their weight over the driving wheels gives good tractive effort. So without much weight in the loco you may suffer considerable wheelslip unless very carefully controlled!
Rgds, Tim
John and Tim thanks for your suggestions, I had thought about weight distribution over the whole loco, and as there are only four drivers you may be right to get maximum weight over them. I think some experimentation once the chassis are complete is the way forward.
Mike
Considering the comments and suggestions regarding suspension / compensation in earlier posts, most applied to six coupled inside framed locos.
The City has outside frames and they need to be modelled faithfully, as there was no room for gear between inside and outside frames, that meant introducing inside axle boxes for springs / beams to bare on thus doubling friction and restricting movement.
The obvious solution to modelling outside axle boxes / horns was to make them work, the chassis now has sprung axle boxes on all four driving wheels
The motor / gearbox is mounted on a slotted cross beam between the inside frames allowing the module to move in the vertical plane and pivot in the horizontal plane. This combination should keep all four drivers in contact with the rails thus providing traction?
The motor and gearbox were made from component's found on e-bay total cost £18.98.
Mike
(https://i.ibb.co/9pzHSCw/P1090849.jpg) (https://ibb.co/9pzHSCw)
(https://i.ibb.co/PjnQKmf/P1090848.jpg) (https://ibb.co/PjnQKmf)
Progress on the City, the wheels were machined from ¼" ali plate with steel tyres they are fixed to axles through extended hubs with grub screws, the axles have squared ends for quartering and the cranks are fixed to axles with countersunk socket screws then faced flush with cranks. The bogie has narrow inside frame for space for light springs on axles to allow wheel side play, the outside frame is just cosmetic the very nice axle box castings are from Walsall.
Mike
(https://i.ibb.co/JBhr6TQ/P1090911-A.jpg) (https://ibb.co/JBhr6TQ)
The boiler smiths have been hard at work rolling and riveting, also the lovely plates have arrived from Guilplates. Much to my surprise the bottom radius of the name plate matches the top radius of the splasher, sometimes you get things right first time!
(https://i.ibb.co/4m7PTz5/P1090920.jpg) (https://ibb.co/4m7PTz5)
Mike
Taking shape nicely, Mike.
What material have you used for the front of the firebox....is it steel?
Guilplates do a good job .... mine were a perfect match for the Bulldog splasher.
I don't recall ever having seen an outside framed GWR 4-4-0 in G3, so "Truro" and "Calcutta" may be "firsts".
At the moment I am held up waiting for a spring casting to arrive from WMI ....... for some reason I was sent only three originally.
Regards,
John.
John
Yes the smokebox door is steel only because I have a bar of 2 1/2" steel, the door is working to give access to the boiler space for battery. It would be fun to run them double headed when finished?
Mike
Quotethe door is working to give access to the boiler space
Ooh, my model doesn't rise to that level of sophistication!
I cast my door and foundation ring in whitemetal (in fact I cast a batch of five doors..... hopefully I shall eventually add a 43XX Mogul, 31XX Churchward Large Prairie and a "Saint" to my GWR collection).
My batteries (in fact everything except motor) are in the tender.
I shall be glad when I have got a coat of primer on it.....the nickel silver, in particular, is badly discoloured from the effects of heat and flux.
Truro and Calcutta as a "double-header" would be a sight to behold....... possibly at the Ampthill GTG?
Regards,
John.
John
You mentioned plans to build a Saint in the future, thought you might like to see my efforts in G1 which was built to Swindon drawings with the idea to coincide with Didcot's rebuild, but they delayed for a year and thankfully celebrated completion early this year. A wonderful day!
Mike
(https://i.ibb.co/dGYNgQC/154601BW.jpg) (https://ibb.co/dGYNgQC)
Mike,
A very nice model ... I can forgive it for being G1!
A Saint (probably a "Lady" series with the original right-angled front drop end and level running plate) is in about eleventh place, behind LNWR, GCR and GNR locos to which I am already committed (as joint projects).
Taking into account my additional commitment to producing LNER/GNR/GCR coaching stock (as well as completing my garden line and sorting out Monkton Priors) I may well expire before I get to starting it!
While on the subject of coaches, what are you planning as a train for "Truro"?
My only GWR coaches are six E147 brake compos (the type sold by GRS as a 2-car "B set ).
I would like GWR "Toplight" gangwayed stock and a Dean clerestory or two and have looked at several options, both home produced and by commissioning laser cut or etched brass sides/ends.
As with everything, time is in short supply!
Regards,
John.
Mike,
Have you yet built the tender for "Truro" and , if not, is it your intention to build a Dean 3000 gallon as it appears in the photo in your earlier post?
The reason I ask is that I need a similar tender for a Collett Goods 2251 class and I am going to be cheeky and ask whether (as a commission at an agreed price) you would be willing to make a second?
After recent bad experiences with a "professional" model-maker, I am hesitant to outsource work but your work is clearly to a very high standard.
Won't be offended if you say "no" (time is precious) but thought it would be worth asking.
Regards,
John.
Footnote: This matter now subject of personal messages.
Inside chassis of City tender, all wheels have side play and centre wheels are sprung, the brake gear is suspended from 1/16in rods which are removable to release the gear for painting and also allow play
The brake shoes are machined on a disc of ali as both sides need to be cut to form the tongue the centre being the reference point.
Mike
(https://i.ibb.co/b7zxh18/P1100202-A.jpg) (https://ibb.co/b7zxh18)
upload images (https://imgbb.com/)
(https://i.ibb.co/YDbRbXx/P1100199.jpg) (https://ibb.co/YDbRbXx)
The tender for the City is complete, there are some detail jobs on the loco to do before a coat of primer is applied, then the final paint job on both.
Mike
(https://i.ibb.co/X4BWJ75/P1100282-A.jpg) (https://ibb.co/X4BWJ75)
(https://i.ibb.co/mz6s9qG/P1100284-A.jpg) (https://ibb.co/mz6s9qG)
Very nice job, Mike.
What Mike hasn't mentioned is that this is just one of a pair of Dean 3000 gallon tenders he has just built.
The other is slightly different in detailing, being in 1930's condition, to accompany a 2251 class 0-6-0 which will shortly be added to my GWR collection.
John.
That's lovely Mike.
Changing to a more design-related subject, I was interested to see that the brakes on this loco are not the more normal 'clench from both sides' variety, as with a bicycle calliper brake clenching the rim, but instead just being pressed onto the trailing edge of the wheel. I can see that this arrangement is better for the wheel bearings than if it were the leading edges of the wheel. Reason? As engineered, the reaction between brake block and tyre (in particular the moment), tends to unload the wheel bearing from its more normal thrust onto the top of the axle. If it ran fast in reverse of course then it would accentuate wear of the wheel bushes, but that was deemed unlikely and probably undesirable by the CME. Just musing!
Cheers, Tim
Tim
I am no expert in running GWR engines, I would have thought the tender brakes were used just as a parking brake as there is no real pressure applied by the hand screw. The engine brakes were activated via a vacuum cylinder and thus more pressure applied.
Mike
GWR Tender Brakes
Early tenders were steam-braked. It is thought that no 2000g or 2500g were ever fitted with vacuum brakes. Dean-era 3000g tenders were not fitted with vacuum brakes until the last few of 1904, which were designed to work with the first 28xx and 29xx locos. It is possible and even probable that more Dean-era 3000g underframes were altered to vacuum-fitting in their later years, and some Dean tops running with later Collett underframes did have vacuum tanks.
In 1906, commencing with the first 3500g tenders, vacuum brakes were fitted as standard.
Vacuum tanks were initially fitted longitudinally, but a transverse orientation became the later standard. On Collett designs (3000g, 3500g and 4000g), the vacuum tanks were longitudinally mounted, but set up within the frames, and not generally visible in a side view. On the later Hawksworths, the vacuum tank was transverse mounted across the frames.
Vacuum brake cylinders were under the shoveling plate, in front of the front axle, but also not visible in general view.
Brake hangars were of the 'twin-strip' form on early tenders, but were changed to the later Collett cast style, probably post-1930. Brake hangars on older tenders were often replaced with the cast ones when repairs and upgrades were made.
Ref: http://www.gwr.org.uk/no-tenders.html
Bob
Thanks for the info, we learn a little every day.
Mike
We do Mike, I did not know either until I read the post. Steam powered brakes? Wow glad they got rid of that idea.
Many (relatively) modern steam locomotives were built with steam brakes .... including the Collett Goods 2251 class. Steam-braked locos were fitted with vacuum equipment (either crosshead-driven pumps or ejectors) to work the train brakes on passenger and fast freight workings. Crosshead driven pumps were a prominent feature on the RHS of many outside cylinder GWR locos.
Away from home and having a hot\ humid and sleepless night, hence typing this at 3am!
John.
City of Truro is complete, my interest lies in the pre grouping era of the GWR and I have built several examples in G1 over the years, but a City has been on the to do list for a long while, finally I have a G3 example.
Batteries are in the boiler splace and accessed through opening smokebox door, the electrics are in the tender also the sound card with the speaker under the coal
It has been a great pleasure to build in this scale, the engines seem almost real.
Mike
(https://i.ibb.co/xCqwbtV/P1100476-B.jpg) (https://ibb.co/xCqwbtV)
(https://i.ibb.co/NSqyPMS/P1100478-B.jpg) (https://ibb.co/NSqyPMS)
(https://i.ibb.co/fNJwtm4/P1100479-B.jpg) (https://ibb.co/fNJwtm4)
(https://i.ibb.co/7KmTvc9/P1100480-B.jpg) (https://ibb.co/7KmTvc9)
It is also a great pleasure to witness the result
Lovely job!
John
Looks very nice in the Edwardian livery with polished brass trimmings and the Indian red frames.
Makes "Calcutta" look decidedly drab in its 1930's green and black!
What Mike hasn't mentioned is that he has built, not one but two, 3000 gallon Dean gallon tenders
at the same time as completing Truro ..... amazing how quickly the model has been completed!
The other tender is destined for my 2251 (Collett Goods) class and is in the later (1930's) condition.
Without Mike's help the 2251 may never have been built.
Regards,
John.
Johns x2
Thanks for your kind comments, I dont know about Calcuta being drab! one part of modeling railway engines and stock is I wish I could do is convinceing weathering, I have tried several times but all I create is a mess
Whilst it is pleasant to see engines fresh out of the shop in reality they did not stay that way for long even with the keenest cleaners efferts, I think engines look better with a layer well aplied dirt!!
Mike