Pennsy A3 Help

[IronMan]

Greetings from Montreal,

I have decided last night to build the A3, I turned 2 wheels in 3/4" scale for practice and they came out great. I need some help on 2 things right now, if someone would be so kind to answer. I will be building the 1.5 7 1/4" version. I have all the steel for the frames and the tender wheels. Before I begin I need to know, how do I get the right measurement for the axles and the frame from the 3/4" scale If I double it up will it be in scale ? Where can I get information on what are the right measurement and how they are calculated, and from what point to point. It may sound like a newbie question, but I got to start somehwere. Thank you in advance.
Regards,
Jean

[Jamie Harris]

Hey Jean, It sounds like we are building the same engine. I am also scaling up the A3 to 1-1/2", 7-1/4" gauge. I have only gotten as far as building 70% of the parts for the tender trucks. I cheated and purchased the tender wheels already machined from Eastern Machineworks. Maybe we could work together some on these projects, I haven't found too many people who are building large A3's yet. Also I have 1-1/2" scale driver castings available if you are interested. They are a bit closer to the prototype than Kozo's wheels are.

About your question, you need to get the track specifications from the club that you plan to run at. I can give you the numbers for our club's track but I don't know if they are universal. It would be best to call the local steam club and ask for their track specs.

Once you have those numbers, you can decide how your wheels ans axles will be built. My pre-machined wheels have about a 1/4" hub on the inside of them and a 5/8" bore. Using the back-to-back and flange-to-flange dimension specified, I determined how wide the axle shoulders needed to be. Since my math isn't always that good I made a test axle and measured all of the dimensions with a set of wheels mounted to it. It seems right. To complicate things I decided to add bearings to the tender truck journal boxes. That is where I stopped about a month ago, I need to get back to work on it.

I haven't thought much about the tender and engine frames yet but I am told that they will be a standard width, no matter what the track gauge is. I am hoping that once the trucks are done that I will just be able to modify the mounting points to fit. You will find that multiplying things by two will get you most of the way there but you will need to put a lot of thought into the parts before you make them.

This board was created to help people building Kozo's engines just like we are. Hopefully we can both post a lot of good information so others will be helped.

Thanks,
Jamie

[IronMan]

Thanks Jamie,

When I saw what you had done, on your webb site that gave me a push toward the A3, then I turned 2 wheels for fun, and now I am hooked ! I will contact my local club, I know they have 7 1/4 tracks. I have just made some calculation and figured it out, using information from " The model steam Locomotive" by Martin Evans. I should be able to get it right. It give out the back to back at 6.800 plus all the other details. I have to curb my enthousiasm a bit an get my research done properly before I ask questions that I can find the answers to if I take the time to look ! Thank you for the offer for the castings, it is a bit ahead of time, I might cast them myself, I have build a Gingery Blast Furnace, just can wait to use it for something! I also might win the lottery in which case I might forego the trouble. I am just begining on this project, its going to be in my spare time, what little I have with 3 kids and the Missus of course, cant forget she who must be obayed. But I am looking forward to exchanging any information and giving any help I can. I am also in the process of making some tools to help me out on this project, refine my lathe, with all the model Egineers magazines I have , a lifetime is not enough, that is why I decided to take the plunge and make these as I go along, so I imagine it is going to slow my progress at times. Bearings sound like a good idea, I have seen plenty of miniature ones on Ebay, from England. Keep taking pictures and posting them It is an inspiration !!
Thank for all your help
Jean

[Bill Holland]

Check out the wheel standards for 7.25" track, and base your calculations from that. This is how I am doing my 1" scale version.

[DavidT]

You have to study the 3/4" drawings and figure how much space is between the frames and driver. I.E. space for lateral movment of the axles. You would double it and work it into your drawing at the 1 1/2 scale reguardless of gauge. I understand that an 0-4-0 does not need much lateral movment because the whole engine shifts around on the tracks. As Kozo says the pilot beams are doubled and the frames are spaced as needed.

[Makinsmoke]

Kozo's Pennsy A3 book has some specifications in the back for those building it in 1-1/2" scale.

[jimbuchanan]

Hi:

I would recommend that you take a look at the IBLS wheel standard. It has been around for some time and most clubs use it for their wheel standard. Tracks are built to this wheel standard. That is to say they are designed to accomidate trains with these wheel standards.

Take a look at www.svls.org/ibls.htm . This is one of many sites if you do Google on IBLS.

[jimbuchanan]

Hi:

I would recommend that you take a look at the IBLS wheel standard. It has been around for some time and most clubs use it for their wheel standard. Tracks are built to this wheel standard. That is to say they are designed to accomidate trains with these wheel standards.

Take a look at www.svls.org/ibls.htm . This is one of many sites if you do Google on IBLS.

[Bill Holland]

That is indeed a very nice wheel standards chart!