Standard RR Gauge

Most of you have probably seen the “joke” or UL that’s been going around about how the “standard” railroad gauge of 4 ft. 8 1/2 in. had developed from the spacing of Roman chariot wheels over time. After several hours of intensive research at railroad historical sites on the net, it’s apparent that there was never any standard developed until the start of the transcontinental railroad around 1855, initiated by the California legislature. In fact, the gauge of the most prominent railroad system in 1831, the Baltimore & Ohio, was 4 ft. 7 1/2 in. What I can’t seem to find is WHY they settled on the present day gauge. (It’s interesting to note also, that several European countries deliberately opted for non-standard gauges to prevent potential enemies from using their rail systems.) Your input please.


I don’t have an answer, but merely a related question. I know that Spain uses a wider gauge rail than most of Europe, but why does Portugal use the standard when the only country that it borders is Spain?

I only assumed the Portuguese and the Spanish bought their equipment from different countries.

See the thread in this forum:

Internet UL Garbage or True? Railroad Gauge.

You won’t find a real answer there though.

Ray (4 ft. 8 1/2 in. = 3 cubits)

I can’t speak to Spain, but Russia traditionally used a non-standard gauge specifically to inconvenience invading armies.

John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams

My copy of “Essential Engineering Information and Data” published in 1991 shows U.S. gage as “56 1/2” between inside of rails, measured 5/8" below top of rail. The gage may vary from 56 3/8" on some high-speed tangent track to 57 1/4" on curves of small radius.

Major railroad gages in use throughout the World (same source):
36" (914mm) - Colombia, El Salvador, Guatemala, Haiti, Honduras*, Panama*, Venezuela*
39 3/8" (1000mm) - Algeria*, Argentina*, Austria*, Bangladesh, Belgium, Bolivia, Brazil*, Chile*, Czechoslovakia*, Egypt*, Ethiopia, France*, East Germany*, West Germany*, Kenya, Malaysia, Peru*, Puerto Rico, Spain*, Switzerland*, Tanzania, Thailand, Tunisia, USSR*, Vietnam, Zaire*
42" (1067mm) - Angola, Australia*, Costa Rica, Ecuador, Gabon, Honduras*, Indonesia, Malawai, Mozambique, New Zealand, Nicaragua, Nigeria, Norway*, Philippines, Rhodesia, Sudan, Union of South Africa, Venezuela*, Zaire*, Zambia
56 1/2" (1435mm) - Algeria*, Australia*, Austria*, Argentina*, Belgium*, Brazil*, Bulgaria, Canada, China, Cuba, Czechoslovakia*, Denmark, Egypt*, France*, East Germany*, West Germany*, Great Britain, Greece, Hungary, Iran, Iraq, Ireland, Italy, Japan, Mexico, Morocco, Netherlands, Norway*, Paraguay, Peru*, Poland, Romania, Sweden, Switzerland*, Syria, Turkey, United States, Uruguay
60" (1524mm) - Czechoslovakia*, Finland, Panama*, USSR*
63" (1600mm) - Brazil*
65 5/8" (1668mm) - Spain*
66" (1676mm) - Argentina*, Chile*, India, Pakistan, Portugal, Spain*

  • Indicates countries having more than one standard gage.

My analysis may be wrong, but it appears to me that most adjoining countries share a common gage, rather than something different from their adjoining countries. Using a different gage than your neighbors’ makes sense militarily, but wouldn’t it also create trouble for international trade?

I don’t have the answer to the 56 1/2" question, yet. I do however have some contacts in the engineering (no, not the guys on the locomotives with the striped hats) departments of several railroads. I have forwarded the question to them and I will update the TM’s as I get information back. Stay tuned.

Abstainer: a weak person who yields to the temptation of denying himself a pleasure.
- Ambrose Bierce

didn’t the various Australian states all have different “standard” gaugues, pre-unification? was New South Wales worried that Victoria would invade them?