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Silver Sidelines

Entry posted by Silver Sidelines

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I was asked this weekend how both my Bachmann Dukedog (9017) and my City performed on gradients. Straight out of the box, the answer is 'With difficulty'.

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Bachmann Dukedog (9017) on local train

9017 is a recent addition to the layout and after marvelling at the detailing and the super smooth performance I was prepared to overlook the fact that my model seemed incapable of hauling any load uphill. 9017 was relegated to shuttling between two stations on my branch line - on the level.

I would investigate further.

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The front bogie detail

Standing the locomotive on a flat surface highlights the likely problem. I haven’t counted the rivets but I am guessing that Bachmann have made a very good attempt at modelling the outside frame to the front bogie with the result that the clearance between the bogie and mainframe is really rather tight.

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Underside of 9017 showing the mounting for the front bogie

Removing the bogie reveals the mounting boss on the underside of the chassis.

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9017 bogie with Bachmann fixing bolt, spring and washer

The bogie is held in place by a threaded bolt which also carries a spring and washer. In use the spring and washer are compressed between the top of the bogie and the mounting boss. With my locomotive standing on a flat surface I was unable to press the front of the engine down on to the bogie suggesting in my mind that front of the chassis was in effect resting on the bogie and that in all probability the front driving wheels were being lifted from the track. To test the theory I reattached the bogie minus the spring and washer. Yes the locomotive would now press down onto the bogie. However the engine appears to be rather front heavy and without any support over the bogie the engine has a tendency to tip forwards lifting the rear driving wheels.

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Plan B – shortened spring on the right

I think the bogie still needs some springing and after a little trial and error I came up with a shortened spring cut from a ball point pen. I also removed the washer – I don’t think there is space for it.

.

Success, 9017 would now haul two old Mainline B Set coaches all the way up my nominally 1 in 40 grade branch line.

http://youtu.be/B9-yeu1GYxk

For the record, the B Set is made up from Mainline coaches fitted with metal wheels and close coupled with Bachmann Mini (long) couplings using the existing fixings.

.

I had wanted a model of City of Truro for some time. Back in the 1980s I had started to add wire handrails to an Airfix kit. I had also purchased a spare Tri-ang bogie from Lord of the Isles for the project. Back in 2010 when City of Truro became available from the National Railway Museum it was just a question of timing and how to break the news to my wife.

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City of Truro – kit of parts

I think City of Truro is a superb model and it glided around smoothly on the level. It did not like my ‘up and down’ layout. However when not ‘posing’ in the shed yard it substituted for my 2251 on the branch line hauling a couple of coaches.

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Underside of the City showing the mounting for the front bogie

Bachmann have used the same construction pattern for both the City and the Dukedog.

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City bogie with Bachmann fixing bolt, spring and washer

To improve haulage capacity I would reduce the spring load from the bogie. There appears to be more space between the underside of the City chassis and the top of the bogie, compared to the 9017 and I have retained a washer.

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City - shortened spring on the right

I am pleased. City of Truro will now handle four coaches, both Bachmann Mk1s or Colletts, taking in the 1 in 60 gradient on the mainline and the 1 in 55 gradient on the reversing loop with only a small increase in power required from the controller to get up the slopes.

http://youtu.be/lOhNbQhgzx0

To answer a specific question the load was increased to five Bachmann Mk1s. With lots of wheel slip it was ‘just’ possible to restart this increased length of train at the top of the 1 in 60 grade. However four coaches looks in keeping with the engine and that will be its limit on my layout.

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Minus the keeper plate

For those of you who have not looked inside the City (or the Dukedog) the wheels are all geared like on a motor bogie. 9017 even includes brass bearings. I am guessing that this arrangement will stop rough running due to faulty quartering.

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Wheel collectors

I have included a view of the copper collectors. The 4-4-0 wheel arrangement, particularly with large driving wheels like on the City seems to me to be rather sensitive to how the chassis is ‘set up’. If the copper collectors are not all equally sprung there might be a temptation for the body of the engine not to be perfectly aligned with the track. My City had a tendency to swing from side to side at the front, which was accentuated when the spring load was reduced. I carefully rotated the front wheels, 45 degrees at a time noting the crank position and measuring the distance across the flanges. The measurements varied between 14.85 and 15.05mm. Gentle pressure squeezing the wheels together at the widest point seems to have been effective at reducing the problem.

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City of Truro on the mainline

Again for the record the Bachmann Collett coaches are running on metal wheels and are close coupled by repositioning the original couplings slightly inboard. The corridor connectors are fabricated from black cartridge paper as described elsewhere on my Blog.

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Richard Mawer

A thorough job as ever, and extremely useful. I have work to be doing whilst Buckingham West mk2 is developed. Thank you.

 

Rich

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Mikkel
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Hi Ray, I don't have either loco but there is always something interesting to learn from your posts. And it's especially nice to see two GWR locos on your layout. That video with the Dukedog is a real pleasure to sit back and watch. Some impressive wheel slipping going on! The Dukedog does look like a very smooth runner though, I hope one will come my way before long. 

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Silver Sidelines

Thanks Mikkel

 

There was some discussion on RMweb recently about the coaches for a GWR City - around 1910.  Now that should just fit with the Farthing Layout?  Now Truro was of course preserved and I think in the early 1960s was 'in steam' and used perhaps between Swindon and Southampton when not hauling railway society specials.  The Dukedog is to my mind a fascinating locomotive - just like a creation by Rowland Emett?

 

Regards Ray

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RonnieS

Hi Ray

I have the chance of buying a Bachmann 31-725NRM GWR 4-4-0 City Class Loco 3440 City of Truro. (The vendor know nothing of our hobby and is  a great distance from me) Has this model tender pick ups? I have great concerns about 4 coupled locos electrically!

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Silver Sidelines
2 hours ago, RonnieS said:

Hi Ray

I have the chance of buying a Bachmann 31-725NRM GWR 4-4-0 City Class Loco 3440 City of Truro. (The vendor know nothing of our hobby and is  a great distance from me) Has this model tender pick ups? I have great concerns about 4 coupled locos electrically!

Thanks Ronnie

 

Yes it has pickups.  There are bits of phosphor bronze that rub on the stub axles of the front and rear pair of wheels.

 

48073658242_c634002118_k.jpg

Edited by Silver Sidelines
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GWR-fan
11 hours ago, RonnieS said:

Hi Ray

I have the chance of buying a Bachmann 31-725NRM GWR 4-4-0 City Class Loco 3440 City of Truro. (The vendor know nothing of our hobby and is  a great distance from me) Has this model tender pick ups? I have great concerns about 4 coupled locos electrically!

 

Ronnie,

               I purchased two of these models, the red underframe and the black underframe from this Taiwan seller and both models were new, unused condition, although no original packaging at all nor the additional pilot bogie.  The service and posting time to Australia were excellent.  From memory less than a week.  I would buy again with confidence from him.

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Mikkel

Mikkel 24,393

Posted (edited)

  • RMweb Gold

Hereby re-instating the lost likes for this very informative post :) 

 

And wondering if a Duke body could be built on the Dukedog chassis...

 

Edited by Mikkel
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DCB

Those tender axle journal pickups look great, far better than the draggy Hornby etc wheelback type.  Are the wheels available as spares?

City of Truro's usual BR days duties were Didcot to Southampton via Newbury passenger trains, work done in earlier years by Bulldogs.

She did run on the MSWJR on a special despite being too heavy for the dotted blue route, (Blue locos at reduced speed) but most MSWJR rosters seemed to involve passenger one way and freight back for which she was not really suitable, with 1 in 65 gradients to Andoversford and through Savernake.

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Silver Sidelines

Thank you all for the comments.  I am thinking that I have missed a link somewhere to a Taiwanese seller?

 

Are the stub axle available - I don't know but speak to Jenni at Loughborough.  I received a damaged secondhand DP1 and was able to buy a replacement shell for not a lot of money.  Sometimes Bachmann are surprising.

 

Cheers Ray

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RJS1977

"There appears to be more space between the underside of the City chassis and the top of the bogie, compared to the 9017 and I have retained a washer."

 

Indeed, there should be as the 'Earls' had smaller driving wheels, meaning the footplate is closer to the ground.

 

My own attempt at scratchbuilding an 'Earl' from Airfix parts (I started well before the Bachmann loco was released - indeed, before 9017 was last overhauled!) has come to a hiatus at the moment because the bogie won't fit underneath and I can't work out which dimension is wrong!

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Silver Sidelines
51 minutes ago, RJS1977 said:

"There appears to be more space between the underside of the City chassis and the top of the bogie, compared to the 9017 and I have retained a washer."

 

I...

Thank RJS - I wrote this Blog a long time ago but yes there was not a problem with the City bogie which had 'space' the issue was with the Dukedog where there was minimal clearance and the washer and spring were taking up valuable space.

 

Cheers  Ray

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Markn

I've just found this after struggling with my City of Truro's haulage capacity for many months! It will now haul 4 Clerestory coaches, each with lighting and pickups on all axles (so a fair bit of drag). Many thanks, you've made my day :-)

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liathach

Hello All,

 

Yesterday, I took delivery of 9003 in GWR Green.  It does look a treat, and with a good decoder, ran very smoothly.  I'm guessing at the gradients I have, maybe 1/50 on 3rd/4th radius curves.  The loco struggled to haul ten wagons or three mk1 coaches with slipping.  As per Ray's previous advice, I tried removing the front truck washer and using a different spring: this  yielded no discernible benefit.  I was thinking of consigning the loco for storage.  However, I had an idea earlier: maybe put a spring between the tender base and the loco drawbar to see if the tender weight would therefore put more weight to bear on the driving wheels. 

 

Initial testing straightaway showed this loco would now smoothly pull five mk1 coaches without the slipping it formerly showed with just three coaches.

 

Adding the spring in that position means that, potentially, the tender front axle can lift due to the loco weight counter-balancing.  Moving the spring sit position to reduce the amount wire inside the compressible area has reduced that effect, without loss of traction.  I will experiment further, with maybe adding weight at the front of the tender.

 

Regards,

 

John

 

 

20210615_155247.jpg

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Silver Sidelines
2 hours ago, liathach said:

 I tried removing the front truck washer and using a different spring: this  yielded no discernible benefit. 

 

 

Thank you John, I am impressed by your thoughts 'outside of the box'. 

 

I love the counter balance idea.  Do you need to do something with the tender to engine wires?   They look as thought they might be pressing down on the track.

 

Rechecking my Blog I see that I removed the washer completely and halved the spring.  With your spring in its new position you could probably remove both the spring and the washer completely from between the chassis and front bogie?

 

It is a super looking model but as somebody remarked when my MGB broke down, "It is a shame it doesn't go!"

 

Cheers Ray

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liathach

Hello Ray,

 

I've been digging in the spares box this morning and put a smaller spring, which seemed to fit better (If the spring provides too much push down on the drawbar, the front axle of the tender is lifted). 

 

I had a heavy 14-wagon coal train with a 28xx running.  This load is far heavier than my previous tests.  The Dukedog will now lift that train without a fuss. 

 

I will tidy the wires, although they are not in contact with the axle or wheels. 

 

Regarding the front truck, I noticed it held the track less smoothly when I placed the original with a finer one giving less tension.

 

I previously had an Oxford Rail Dean Goods, which also could not pull anything near a decent load.  Be interesting to see if a spring against the tender drawbar would work with that.

 

Cheers,

 

John

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RJS1977

I'll admit I was disappointed when I first bought my Oxford Dean - it struggled to pull three Triang clerestories and a parcels van.

 

However having replaced the parcels van with one of the new Hornby generic full brakes, it pulls the train fine - though it may also be that more running in has helped.

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Silver Sidelines
6 hours ago, liathach said:

I previously had an Oxford Rail Dean Goods, which also could not pull anything near a decent load.  Be interesting to see if a spring against the tender drawbar would work with that.

 

 

6 hours ago, RJS1977 said:

I'll admit I was disappointed when I first bought my Oxford Dean - it struggled to pull three Triang clerestories and a parcels van.

 

 

Thank you John and RJS.  The Oxford Dean Goods is interesting and I did write a Post about it:

 

https://www.rmweb.co.uk/community/index.php?/blogs/entry/20993-weighing-up-the-dean-goods/

 

When I wrote it someone, probably on RMweb commented that they thought the tender was propping up the engine and hence lifting the rear wheels off the track.  This was certainly the case with my model and was solved simply by slackening off the tender to engine drawbar screws.  I also managed to add a little bit of lead inside the boiler.  There is an old video of mine.  It gets interesting after 2 minutes when it starts to climb the gradient on my 'hidden' reversing loop which is around 1 in 60  / 1in 56.

 

 

 

Cheers Ray

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