Dear Luke Hu,
Strictly by the math, a Union Pacific 4-8-8-4 4000 Class “Big Boy” could haul 4800 tons up a 1% grade. Let’s say that each passenger car carried 65 people and weighed 150,000 lbs (some average figures). This would yield 64 passenger cars or 4160 people. Keep in mind that a Big Boy is at the very largest end of the spectrum, and that though it would have no problem with brakes for 64 cars (it could handle about 250 probably), steam heat might not make it all the way to the rear cars, and slack action, the banging of cars together and apart, would be very uncomfortable at the rear with all those cars. Also, the Big Boy was primarily a freight engine (only in rare emergencies did it pull passengers), and had a top speed of 80 mph, while an FEF-2 (the UP’s passenger engine on flagship trains) could EASILY do 100 mph, it would probably only be able to haul 12 cars (the official number) up a 1% grade. Now, on level ground, let’s just say that amazing things can happen…
Sincerely,
Daniel Parks
Is there a consensus that diesel hauling passenger cars is a rarity above the low twenties of cars carried – and for practical reasons like brakes and heat?
I think we need to give Luke Hu something a bit more toothy.
HI Luke Hu,
I hope, your students are still off school, so my contribution to this interesting question won’t be too late.
For any practical purposes, platform lengths, station track time limited availibilyty & timetables & elderly passenger catcing the train abilities to reach the furthest car ,I would say twenty is the limit.
IF we ignore these considerations, I think a N&W classical Y6b steam 2-8-8-2 could get easily run some 80 lightweight European pre-war wooden passenger cars at 50mph each sitting some 70 persons. No steel wheels on iron rail locomotive can draw any number of cars because there is a problem with tiny traction. Even the the Y6b would use it’s sandbox to get moving with such a load.
To run 11 heavy cars past 200 mph, a TGV still needs double the power of Y6b. Still it could not get the same train moving as Y6b did.
Erudite, but was that really layman-friendly?
I think your best answer would be to check out the Ringling Bros. train.
While not exactly “passenger cars” ,its still varnish, and I believe their trains
are 2-3 miles long![:)]
It’s fun to split hairs, but not at the expense of middle-schoolers.
Most passenger locomotives are designed to carry 10-15 cars, although there are exceptions. The legendary GG-1 electric locomotive of the 1930s was retooled in the 1950s so that (some of) the fleet could carry 20 “heavyweight” steel coaches. (Today’s Amtrak “Amfleet” day coaches are lightweight by comparison.) I challenge readers of this forum to name any contemporary, regularly scheduled American passenger train that typically hauls more than 20 cars behind it. In practice, not in theory.
Beyond 20, things get really problematic for anything other than an engine and a “booster” (many of the early designed diesel-electrics of the 1940s called for a second engine — in effect an extra charging and motive force). Tell your students as well that most locomotives today are not purely Diesel as in diesel truck, but “Diesel-electric” - that is, the diesel engines power dynamos that drive the train with electric power.
I realize my answer is not sufficient for circus trains, excursion trains, Tweetsie Railroad, and THINGS THAT ARE IMPOSSIBLE like hauling “prewar wooden” European passenger cars with an American steam engine from the 1940s.
If you don’t like the parameters I’ve given then fine, but for God’s sake remember you’re talking to a history class of middle schoolers, not students of the railroad industry per se or locomotive designers or electrical engineers. We must enlighen Mr. Hu before we entertain and educate each other. - a.s.