Caterpillar D6A

[tankbarrell]

Thanks for that Jakko! I knew the 1T serials don't appear in normal Caterpillar productions lists but had just thought they were all D7s. Good to know the facts.

[David Herbert]

I am sure that I have seen standard un-armoured D7s with 1T numbers but I didn't record the actual number and of course they could have been rebuilt from armoured ones. Post war there were also 3T and 4T un-armoured D7s. I wonder what the 2Ts were if that designation was used?

David

[tankbarrell]

2T's were standard D4. 2, 3 and 4T serials all appear in Caterpillar production lists but 1T's do not.

[Dave Newcomb]

There is an extensive Cat museum in the Powerland complex in Brooks, Oregon Those folks may be a help. Dave [in Oregon USA]

[Jakko Westerbeke]

Originally Posted by tankbarrell

I knew the 1T serials don't appear in normal Caterpillar productions lists

They do for the D6(Armored):


(previously posted here)

I haven’t seen a list for the D7-series, but I would suspect they appear there too?

Originally Posted by David Herbert

I am sure that I have seen standard un-armoured D7s with 1T numbers but I didn't record the actual number and of course they could have been rebuilt from armoured ones.

According to this page, only the armoured ones had 1T prefixes.

Originally Posted by David Herbert

Post war there were also 3T and 4T un-armoured D7s.

Actually from 1944, according to that same site. I get the impression from that that 3T was the next prefix used for the D7 after the 3M series reached 9999 (the 1T D7s are basically 3M-series tractors with armoured cab etc.) while 4T is from another factory.

[Tim Bell]

2C is for the Medium M4 tank transmission units.

[tankbarrell]

But is that book a Caterpillar publication? I have two different lists compiled from Caterpillar records (apparently) and none of the 1T serials are mentioned.

[Jakko Westerbeke]

Originally Posted by tankbarrell

But is that book a Caterpillar publication?

I don’t know for sure, but I suspect it is. I got the photo from one of the guys restoring this bulldozer, and they’ve got pretty short lines to Caterpillar. They also got copies of factory drawings of the overall layout, for example:

357DF79C-6370-4F91-88A4-6ADDF57E1F4F.jpeg

45BE7B25-3CD9-416C-8157-DB9272E509F2.jpeg

D7B6A252-0728-4F34-A31F-F8B5A32F054C.jpeg

342C39F3-6D6D-4013-B847-FF5B1928503E.jpeg

[David Herbert]

Those drawings are marked Caterpillar Tractor Co. I had thought that the armour was designed, made and fitted in the UK, possibly by Jack Olding Ltd. I can't see a reason for Cat to give a separate code to armoured tractors and only add 'SP' to other variants like pipe cranes which are just as different to base machines. There were lots of standard 7M D7s used by the military so it isn't because they were military contract.

David

[Jakko Westerbeke]

Originally Posted by David Herbert

Those drawings are marked Caterpillar Tractor Co. I had thought that the armour was designed, made and fitted in the UK, possibly by Jack Olding Ltd.

That is a common misunderstanding. Jack Olding was the UK importer for Caterpillar, and fitted some D8s with waterproof hulls to use as BARVs, which is where I suspect the confusion comes from. However, as I understand it, the D6(Armored) and D7(Armored) were entirely built by Caterpillar itself in the USA. Caterpillar having made drawings of the armour is a strong indicator, IMHO. (Note that there are some mistakes in the drawings, mainly the rear view: the hydraulic cylinders are too far apart, most likely because someone overlooked that the bonnet is narrower than the rear plate.)