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Adding weight to a loco with limited space


LukeB
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I've just finished painting and putting together one of @bmthtrains - David 's 3d printed N gauge Harsco Rail Grinders. It's designed around a Tomytec TM05 chassis but when I bought a chassis this wasn't available anywhere, either in the UK or worldwide. I've had to modify a Tomytec TM-TR05 instead. This is a bulkier unit and I had to cut the front bogie off and reattached it to make it fit.

 

The chassis ran fine on its own but with the body on, and especially with the second car attached, it struggles to run, particularly on curves. It doesn't seem to get enough traction - when I put a finger on it it runs fine. Also, when it's run with the rear bogie of the powered car first, there doesn't seem to be enough weight to hold the bogie down and it pops off the track when it sets off.

 

Based on it working when I put a finger over the powered bogie, I think it needs more weight, unless anyone has any other ideas what might be going wrong. At the moment the motor mechanism has a layer of blutack as thick as possible above it, filling the body of the car. Is there something heavier I could use here? Or would I be better moving the blutack and only putting it over the rear bogie, removing weight from the front? Space in there is very tight - there's only a few mm above the top of the chassis and the roof.

 

 

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10 minutes ago, Barclay said:

If there's a few mm gap then there might be room to stick in some sheet lead on the underside of the roof. A small roll of builders' lead flashing isn't exactly cheap but will last many years !

 

Might be easier, certainly cheaper, to find a roofer working locally, and ask for some off-cuts.

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27 minutes ago, LukeB said:

Would even a small strip of lead weigh enough? I tried it with less weight over the non driven bogie tonight and that made it run even worse so it clearly needs more weight everywhere. 

 

It should weigh a fair bit more than the same sized piece of Blu-Tak, so removing that,

and replacing with the lead, will make a difference.

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Skips are a good source of flashing. Church roofs used to be but now they all seem to have CCTV.  I cut the flashing with a Stanley Knife, or scissors.  if the lead is too thick or multiples of layers are too thick hammering it can compress it nicely.   If you want a specific shape then melting the flashing with a blow lamp and dripping the molten lead into a wooden mould works well.   Probably best not to set the shed on fire or drop molten lead on the kitchen carpet.

I guess depleted uranium is heavier if you can live with the radio activity, or gold might get the job done if the wife has a drawer full of bling she never wears.

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I’ve just done a 009 class 70 which uses a kato chassis and I had a similar issue, chassis run fine, body on and it didn’t go anywhere near my spiral, I ordered some DCC Concepts lead shot which I’ve poured into the top of the body shell while upside down and secured with rocket glue pva,, also added a piece of card below for added security but not really needed

 

add to that a tiny magnet on the drive side of the chassis to work with the power bases I have and it now breezes up the hill 

 


 

Edit: video added 

Edited by big jim
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Interesting! 
 

i assume the stuff DCC Concepts sell is a ‘safe’ form of shot then, the item I got is DCT-LLC liquid lead shot and the instructions recommend PVA amongst other ideas to secure it, will have to see how it goes over time


https://www.dccconcepts.com/product/liquid-lead-shot-500gm/

 

Edited by big jim
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32 minutes ago, Jol Wilkinson said:

Lead shot and PVA are a recipe for disaster. Over time they react and expand, for example sufficiently to split a seam soldered etched boiler. 

 

A different adhesive such as an epoxy adhesive, doesn't present the same problem. 

 

Mek-pak and similar plastic solvents with anglers' lead shot is also a no-no, speaking from experience.  I thought the DCC Concepts stuff was lead-free, though I think the problem is with the adhesive rather than the weight.

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19 hours ago, DavidCBroad said:

Church roofs used to be but now they all seem to have CCTV. 

 

I am still using some lead I helped recover from a church (legally!)   It came from the organ pipes, the building having been sold to some competing religion that does use that sort of music.  The bulk of the lead had been crudely cut out already and sold for scrap - we just removed the smaller pieces left behind after the pipes were cut.  Seemed like vandalism at the time, but the organ had already been wrecked.

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As a way of gauging how much weight will help, if you have a digital kitchen scale they typically weigh from 3gm upwards. Using something to protect the scale or its weighing pan (a piece of paper or card should do), first weigh

the current blutack and then temporarily attach the blutack to the top of the body and use the blutack to attach coins (or stacks of coins) - try both ends, and just one end, to see what works best. Then you can weigh whatever works best (and weigh the lead to confirm it is in the same area).

 

A further thought - in 009 there have been reports of (steam) locomotive chassis being worn out comparatively quickly by putting too-heavy whitemetal bodies on them. So ideally enough weight to run reliably, but no more.

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Unobtainium is best, or collapsed star material.  I use liquid lead held in place with Blutak or Milliput, and pack as much in over the driving wheels of every RTR loco I have; it has always improved pickup and performance, although this is in 4mm where the mechs are perhaps a bit tougher than in N or 009.  An exception is the new Bachmann 94xx, a very heavy loco as supplied, and I have not yet superballasted mine!

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