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Acceptable axle loading

George Coles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Fri 21st Oct 2016, 3:46pm
Acceptable axle loading

I've just acquired a part-built Bo-Bo loco to complete. I was told it was heavy - it is! Built of 10mm plate, it weighs in at over 200kg. This could rise a few kgs, so the axle loading could be as high as 60kg per axle. As many club, and some commercial, railways use aluminium rail, I wonder if I am going to be limited to the tracks I can visit. Does any-one have any details of actual weight limits on particular railways?

George C
4943
 

Replies To This Post

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Fri 21st Oct 2016, 4:42pm

I'm not aware of any railway specifying axle loading restrictions, we have none at Sheffield. We did look at this in the past and realised that passenger carriages can exceed 60g per axle when fully loaded with no ill effect to the track. As you have just been to the AGM you'll have seen the Beer Heights carriages, which are articulated and heavy in themselves: each takes four passengers, so when fully loaded the weight of eight passengers is spread over 6 axles; if each weighs 60kg that's an 80kg per axle loading on aluminium rails plus the weight of the carriages.
 

George

Joined: 27-01-10

Topics: 0

Replies: 20

Posted: Fri 21st Oct 2016, 4:59pm

Some clubs in Holland are considering a maximum of 150kg per axle. Some of the track is more lightly laid with larger distances between ties. Also the higher axle load results in increased wear on points and curves. Of course there are other factors at play also like larger distances between the coupled driving axles and rear buffer beam.
Mind you at my club there are BoBo's that weigh in a hefty 600kg but a bogie loco generally is easier on the track. And yes passenger carriages can have considerably larger axle loading especially the articulated sets. However also because of the articulation the side forces are partly reduced.
Regards
 

George Coles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Fri 21st Oct 2016, 4:59pm

Thanks Mick

I have seen a railway indicating a max axle loading in the past, but cannot recall where!

I weigh 74kgs, and there were heavier (Peco) people standing on their rails to chat, so clearly not a problem there. However, many tracks I have visited request visitors NOT to walk on the rails, so I wonder if those railways are less substantially laid? Lighter ballast/less foundation?

George
4943
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Fri 21st Oct 2016, 5:18pm

I think "not walking on the tracks" is more from a safety point of view, than constructional. People also will tend to kick the ballast about when walking on the tracks. I agree with Mick about axle loadings, and George makes the point about sleeper spacing being important too.
 

Lambrail

Joined: 9-02-08

Topics: 8

Replies: 12

Posted: Tue 25th Oct 2016, 8:03pm

What did you buy George? Sounds intriguing.
 

George Coles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Tue 25th Oct 2016, 8:27pm

An abortive attempt to produce a 5" gauge loco, which would be suitable for running on raised and ground level track in a 'rescue' role. As built it weighed 206kg without its batteries! So it would have been impossibly heavy to use on a raised track as a rescue loco - how would one get it to its rescue position if several other locos were between its base location and the failed loco - levitate?
It was, of course, designed(!!!) by a committee, so, inevitably, the result was not equus ferrous, but camelus dromedarius.
Given time, and lots of patience, I hope to correct the engineering errors (and this was built by a model engineering society) and rebuild it to 7.25" gauge, as a usable, and useful, loco. Watch this space, but don't hold your breath - I have too many 'winter projects' already. (Where have I heard that before?)

George C
4743
 

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Tue 25th Oct 2016, 9:52pm

I have dug up some calculations from way back when we had 20mm x 10mm mild steel bar rail at Sheffield. Deflection with a 1000lb wheel load on that rail with sleepers at 6" centres is .010". The formula is deflection D = WL3 divided by 4Ebt3, where E is Young’s Modulus (for mild steel E is 28,000,000 lb/in2 ), W = load, L - span between sleepers, b = width of rail, t = depth of rail. N.B. the 3's represent 'cubed' but the website has shown them as ordinary numbers. Hope that helps!
 

George Coles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Wed 26th Oct 2016, 8:16am

Mick, thanks. Ten thou. is not going to be a problem. I had forgotten how to work that out -haven't used Young's Mod for (er) decades! From the responses, 'Drom' isn't going to be problem, even on ali track.
George
4743
 

George

Joined: 27-01-10

Topics: 0

Replies: 20

Posted: Thu 27th Oct 2016, 6:51pm

6 inch spacing? More like 10 to 12 inches dear sir. However if memory serves 25 or 30 x 15 mm cross section.
What would that do and when do we go from elastic to plastic?
What is the influence of the forces by a steam locomotive (vertical component of the movement)
Static I am sure you're right, however how bis is the dynamic influence especially going round curves. I think we have all seen it happen when the gauge appeared to grow and the loco or bogie with beautiful model wheels sank between them.
Regards and thanks for the calculation
George
 

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Thu 27th Oct 2016, 9:12pm

You're welcome. Just for the record, at Sheffield our sleepers are spaced at 6" centres as we are dual gauge 5" and 7¼". Nowadays we use Cromar White 27mm steel flat bottom rail on recycled sleepers.
You're welcome. Just for the record, at Sheffield our sleepers are spaced at 6" centres as we are dual gauge 5" and 7¼". Nowadays we use Cromar White 27mm steel flat bottom rail on recycled sleepers.
 

George Coles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Fri 28th Oct 2016, 6:49am

Thanks Mick. To avoid confusion, may I point out that there are at least two Georges on this thread: myself (George Coles) and George (who?)
That's why I sign off as George Coles, or George C with my member number.
George Coles
4373
 

George

Joined: 27-01-10

Topics: 0

Replies: 20

Posted: Fri 28th Oct 2016, 9:49am

Hi Mick,
We also are dual gauge but with the much higher spacing. I am curious about the defection.
Hi George C
This and earlier posts are by me
George van der Hauw (Holland)
4544
 
 
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