Dr Gerbil-Fritters Posted October 2, 2018 Share Posted October 2, 2018 How about a Garratt based on the running gear of a pair of Standard 2MT 2-6-2s? And for passenger work, 2-6-4+4-6-2 based on the 80xxx... 2 Link to post Share on other sites More sharing options...
RMweb Premium Clive Mortimore Posted October 2, 2018 RMweb Premium Share Posted October 2, 2018 How about a Garratt based on the running gear of a pair of Standard 2MT 2-6-2s? And for passenger work, 2-6-4+4-6-2 based on the 80xxx... With a Britannia boiler slung between them. Link to post Share on other sites More sharing options...
sir douglas Posted October 2, 2018 Share Posted October 2, 2018 i read some where recently that mr Garratt first went to kitson but was rejected as they were already happy with the meyer so then went to beyer peacock and the rest is history, so in a different world it could have been Kitson-Garratt 1 Link to post Share on other sites More sharing options...
Satan's Goldfish Posted October 2, 2018 Share Posted October 2, 2018 With a Britannia boiler slung between them. I've used the 4_6_0 tender 4mt rather than the big tank, plus Britannia trailing wheels to make it a 4-6-2+2-6-4. Removed a section of boiler from the Brit too because it just looked wrong. I'm sure somebody will confirm my suspicion that it has too many cylinders... It just confirms what I already know; I'm not good at drawing Garratts! It might look a bit better and keep the original Britannia boiler if it was a bit asymmetrical with the boiler positioned further over the front wheel set, plus an inside frame trailing wheel set on the front unit. Thoughts? Overall wheelbase is the same, just a bit more boiler, and a bit less water capacity at the front. 6 Link to post Share on other sites More sharing options...
RMweb Gold Corbs Posted October 2, 2018 RMweb Gold Share Posted October 2, 2018 The problem is there was never a Garratt that used the same boiler as a conventional loco, all (standard gauge) Garratts had the same design of boiler that was quite distinctive. Link to post Share on other sites More sharing options...
Dr Gerbil-Fritters Posted October 2, 2018 Share Posted October 2, 2018 I was envisaging something more compact, with smaller driving wheels - perhaps something like this: from this excellent resource. 3 Link to post Share on other sites More sharing options...
brack Posted October 2, 2018 Share Posted October 2, 2018 The problem is there was never a Garratt that used the same boiler as a conventional loco, all (standard gauge) Garratts had the same design of boiler that was quite distinctive. Short tubes, fat in diameter, big deep firebox, unencumbered ashpan. Essentially the optimum shape for a boiler in that it puts more water nearer the fire. On a conventional loco you can't do this very well as there are wheels to fit underneath. On a garratt you have a pretty free hand in boiler design as there's only a girder frame and some pipes to go around it, so you can make the boiler fill the loading gauge. A double 10 coupled (or more) mallet is a disaster because the front end of its long skinny boiler is too far from the firebox (so it'll be a poor steamer) and the throwover on curves is horrific. The Santa Fe tried both concertina and ball and socket joints in the boilers and then gave up on huge mallets. Garratt definitely spoke to kitson - I think there may have been some tenuous prior connection, but I think he may have visited other loco works too. Not hard to see why he was rejected - a paper patent, no prototype from a man with little design experience and no money to help fund it. Remember that the kitson Meyer certainly wasn't kitson's idea, but was down to Robert Stirling (possibly inspired by a one off loco Baldwin had built). 1 Link to post Share on other sites More sharing options...
rockershovel Posted October 2, 2018 Share Posted October 2, 2018 (edited) A man with a paper patent, not much experience and no funding... but speaking to a manufacturer with plenty of experience and funds, and a perceived market with no product to supply it.... Edited October 2, 2018 by rockershovel 1 Link to post Share on other sites More sharing options...
Niels Posted October 2, 2018 Share Posted October 2, 2018 (edited) How about a Garratt based on the running gear of a pair of Standard 2MT 2-6-2s? And for passenger work, 2-6-4+4-6-2 based on the 80xxx... Giesel Gieslingen of ejektor and https://de.wikipedia.org/wiki/BB%C3%96_214#/media/File:Strasshof_2007_12.10.jpg fame stated that two independent six coupled locomotives were less sure footed than a single ten coupled. LMS Garratts versus BR9F prove the point. Being an imaginary site maybe couple the two power bogies like a Heissler and have high pressure cylinders at the cab end and low pressure at the front end. Edited October 2, 2018 by Niels Link to post Share on other sites More sharing options...
Ohmisterporter Posted October 2, 2018 Share Posted October 2, 2018 There is a limit to how big a Garratt boiler can be because the footplate crew has to see past it for signals and the road ahead. In South Africa the big GMA Garretts were often run with cab leading and were turned on a wye at the end of each run but not only to enable the crew to see ahead. The reason for this was that with the many tunnels on some routes the cab would fill with smoke and become vary uncomfortable for the crew. Having the chimney behind the cab helped to alleviate this. There are many photos of SAR Garratts towing a water tank particularly across the desert lines where water tanks were not always available. Sometimes quoted in American sources is their reluctance to use tank engines like a Garratt was because as the water is used up the adhesion weight falls. Exactly as happens on a diesel but surely a nation with consummate engineers could find a way round this. 1 Link to post Share on other sites More sharing options...
brack Posted October 2, 2018 Share Posted October 2, 2018 The GM and GMA/M classes were deliberately designed to use an external water supply (auxiliary tank) in order to keep their weight/axle loading down for use on light(er)weight track. The rear engine unit only has coal in, so the only water carried is in the tiny front tank. The batch of NGG16s ordered for/by the Tsumeb Corp were also designed with increased coal capacity for longer range at the expense of water capacity, so they were intended to have an auxiliary water tank. Other garratt designs generally did not use an auxilliary water tank Link to post Share on other sites More sharing options...
Gibbo675 Posted October 2, 2018 Share Posted October 2, 2018 How about a Garratt based on the running gear of a pair of Standard 2MT 2-6-2s? And for passenger work, 2-6-4+4-6-2 based on the 80xxx... Dr Gerbil-Fritters, I currently have various bits of 9F and the purchase of some 4MT 2-6-0 kits is being considered as a juxtaposition to the mallet. However since reading the post upon this thread my question now is, do I do a BR [non] Standard Beyer Garrett or a Kitson Meyer ? My latest Bullied bash is now delayed due to the lacquer blooming on final coat. Gibbo. Link to post Share on other sites More sharing options...
Gilwell Park Posted October 2, 2018 Share Posted October 2, 2018 Dr Gerbil-Fritters, I currently have various bits of 9F and the purchase of some 4MT 2-6-0 kits is being considered as a juxtaposition to the mallet. However since reading the post upon this thread my question now is, do I do a BR [non] Standard Beyer Garrett or a Kitson Meyer ? My latest Bullied bash is now delayed due to the lacquer blooming on final coat. Gibbo. Hi See post 3519, it really works. Link to post Share on other sites More sharing options...
RMweb Gold Corbs Posted October 2, 2018 RMweb Gold Share Posted October 2, 2018 http://www.rmweb.co.uk/community/index.php?/topic/14790-imaginary-locomotives/?p=3287221 1 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted October 2, 2018 RMweb Premium Share Posted October 2, 2018 Giesel Gieslingen of ejektor and https://de.wikipedia.org/wiki/BB%C3%96_214#/media/File:Strasshof_2007_12.10.jpg fame stated that two independent six coupled locomotives were less sure footed than a single ten coupled. LMS Garratts versus BR9F prove the point. Being an imaginary site maybe couple the two power bogies like a Heissler and have high pressure cylinders at the cab end and low pressure at the front end. IMHO Pitting one of the best 10 coupled locos against one of the weakest Garratts is hardly a good comparison. Keith Link to post Share on other sites More sharing options...
Gibbo675 Posted October 2, 2018 Share Posted October 2, 2018 Hi See post 3519, it really works. Hi GP I know, we exchanged some note and points about it ! Gibbo. Link to post Share on other sites More sharing options...
Satan's Goldfish Posted October 10, 2018 Share Posted October 10, 2018 Question: is there any mechanical advantage to having the largest driving wheels possible? I don't mean on express steam as I understand it there, I mean modern diesel/electric locomotives. If a fictitious express locomotive had jackshaft drive then it makes sense for similar reasons to a steam locomotive. But what about the more common individual traction motor axle driven locomotives? Any advantage to doubling the 'standard' wheel diameter there? Ta 1 Link to post Share on other sites More sharing options...
Gibbo675 Posted October 10, 2018 Share Posted October 10, 2018 Question: is there any mechanical advantage to having the largest driving wheels possible? I don't mean on express steam as I understand it there, I mean modern diesel/electric locomotives. If a fictitious express locomotive had jackshaft drive then it makes sense for similar reasons to a steam locomotive. But what about the more common individual traction motor axle driven locomotives? Any advantage to doubling the 'standard' wheel diameter there? Ta Hi Mr Goldfish, The reason that wheels are generally around three feet in diameter is inertia. The amount of energy required to both accelerate and decelerate is increased in relation to the diameter in the way a fly wheel of great mass and diameter is a store of energy via rotation. Small wheels are not particularly good for high speed due to bearing speed constraints. Gibbo. https://en.wikipedia.org/wiki/Moment_of_inertia https://en.wikipedia.org/wiki/Momentum Link to post Share on other sites More sharing options...
Satan's Goldfish Posted October 10, 2018 Share Posted October 10, 2018 Thanks Gibbo, that makes sense... ###### up my idea of imagining mainline diesels and electrics in a 4-8-4 format though! Link to post Share on other sites More sharing options...
RMweb Gold Budgie Posted October 10, 2018 RMweb Gold Share Posted October 10, 2018 Thanks Gibbo, that makes sense... ###### up my idea of imagining mainline diesels and electrics in a 4-8-4 format though! Not necessarily. What about the Fell? Link to post Share on other sites More sharing options...
Satan's Goldfish Posted October 10, 2018 Share Posted October 10, 2018 Thought that had con-rods? I know the earlier Swiss electrics used bigger drive wheels and smaller unpowered wheels in some cases (Ae4/7 etc), wondered if there was a benefit to it. Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted October 10, 2018 RMweb Premium Share Posted October 10, 2018 Hi Mr Goldfish, The reason that wheels are generally around three feet in diameter is inertia. The amount of energy required to both accelerate and decelerate is increased in relation to the diameter in the way a fly wheel of great mass and diameter is a store of energy via rotation. Trying to get 6'6" wheels underneath the body of a diesel or electric loco could prove troublesome. Keith Link to post Share on other sites More sharing options...
RMweb Gold Budgie Posted October 10, 2018 RMweb Gold Share Posted October 10, 2018 Thought that had con-rods? Can you call it 4-8-4 if it didn't have con-rods. When the rods joining the middle two drivers were removed it became a 4-4-4-4. Link to post Share on other sites More sharing options...
Satan's Goldfish Posted October 10, 2018 Share Posted October 10, 2018 Can you call it 4-8-4 if it didn't have con-rods. When the rods joining the middle two drivers were removed it became a 4-4-4-4. My very basic reference to con-rods in this context is more down to rotational speed of the wheels and the effect they have... (I've had a couple of rums, terminology isn't my strong point now). Link to post Share on other sites More sharing options...
Mr_Tilt Posted October 10, 2018 Share Posted October 10, 2018 Trying to get 6'6" wheels underneath the body of a diesel or electric loco could prove troublesome. Keith Bullied managed to get 5'1" drivers under the body of a psuedo-diesel with the Leader. Mind you, it was a LONG way off the ground! 2 Link to post Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now