can a 5ft gauge steam locomotive be converted to standard gauge ?

Yes. The amount of difficulty will vary, of course...…. depending on how it is constructed.

The Alaska Railroad got about 25 2-6-0s from the 5 foot gauge (Panama) Isthmus Canal Commission railroad, ca 1915. Driver gauge was changed with wide tires. It appears they did the same on the lead trucks. One problem is that the wider drivers would would climb up on the ice that formed on the outside of the rails at grade crossings.

The five foot gauge USSR USATC S-160 Consolidations widened the frame spacing
and used different cylinder blocks than were used on the standard gauge version.

http://www.alaskarails.org/pix/former-l ... index.html

I believe the "Russian" Decapods were re-gauged from 5' to standard by adding wider tires.

Just stay way from self-guarding switch frogs.

Self guarding frogs would also be an issue using wider tires. WM Shay 6 was built that way, and I understand her deadhead move from Baltimore to Cass took quite some time, gently easing over many switches.

thinks guys but what about the frame i fond a this on the same topic 3 years back
and it said the frame need to be cut to size i would like to know if this is truth or not and i would like to know the different ways a steam locomotive can be regauged .

The width of the frame and width of the saddle / cylinder castings have most to do in determining whether or not the locomotive can be easily (relative term) regauged. The saddle is set up to hold the frames at a designed width, which then runs down the entire frame of the locomotive. If the frame was designed to be narrow enough to allow for extra wide tires to be applied to reduce the gauge, you are lucky. If it wasn't, you are in for a lot of heavy work and might as well build a new everything under the boiler recycling some useable old parts if possible, like wheel centers and valve gear.

So how would adding wide tiers to a alride wide wheel base convert it to a narrow 4'8.5"?

The width of the tires allows the flange to be further back towards the center line of the locomotive. The wheel centers could have ordinary width tires on them for flanges at the original 5 foot gauge. Think from the outer surface of the wheel center in rather than out.

Just noticed this thread. In 1989 NSRM was looking into acquiring a lend/lease locomotive available in Vladivostok through a British broker. The locomotive was available with the standard gauge wheel sets and the broad gauge set as well. It appears that the Russians changed out wheel sets to go from one gauge to the next. I imagine that the standard gauge set had longer crank pins but I don't know for sure.

The locomotives (there were several) were available for pretty cheap but NSRM decided that they didn't want one afterall.

CCdW

do you know if the locomotive are still there ?

Not a clue. Been a long time. They were decapods.