what if multiple units had not been invented?

Interestingly part of the train behind Met 1 was / is a multiple unit.

The majority of that train consists of so called Chesham set carriages, (their last duties were part of 2 fixed 3 carriage rakes (units) on the Chesham branch) A better name for them would be Ashbury Carriages the name of the manufacturer although one of the carriages was built by Cravens.

These carriages are interesting as they are close coupled using a rigid bar, only the outer carriages have full length buffers and normal couplings. This feature would have made them more likely to run in fixed rakes (units). More interestingly these carriages were converted to electric operation, The Brake Third becoming a Driving Motor Third and the Third becoming a Driving Trailer Third. A twin sister of the Third can be seen at Covent Garden with it's Motormans compartment intact. So for most of their operating lives were Electric Multiple units.

More information here, www.bluebell-railway.co.uk/bluebell/bash/hist.html

While in this country we have fixed multiple units, a look at the Swiss Railways will see not only Loco hauled stock, but variable multiple units.

N.B. I spent a few years working as a carriage joiner in the same shed the Ashbury carriages were stored and restored (rebuilt).

Push - pull locos?

The steam auto-trains and push-pull units worked by a system of bell signals, didn't they? Two man operation needed

Well OPO would be possible with terminal loops or a loco at each end, but stepping back would presumably be extensively used in the latter circumstance.

Ha! I hate making spelling mistakes in posts. Once I've spotted one I have to do something about it Chris!

If both locos are under power there would have to be a driver in each one, so double manning would be necessary. (quick turnrounds would be possible without the need for stepping back though!)

The alternative is for the rear loco to be "dead-in-train", (or at least idling) which results in a lot of dead weight being trundled about. If not designed for it, constant idling is bad for diesel engines - when Class 91 production got ahead of schedule, the Mark 4 coaches were not ready, so they were couples to HST sets, minus one power car. The other was retained to act as a DVT and to provide power for lighting etc (which the class 91 couldn't do for HST stock, but they started developing oil leaks so they were arranged to run under power, resulting in a super-powered class 43+91 pairing!)

Maybe if MU control were never invented, track-based control would have happened sooner - with all powered cars taking signals from the track instead of just the leading one - think of the way a double-header is controlled on a Hornby-Dublo layout! So maybe, rather than double manning, in our non-mu world there would be no drivers at all!

...and physical coupling rods which ran from driving position to steam traction unit.

Being steam powered they needed a fireman, as well as the driver.

btw, trams were usually double ended but was that multiple unit, even for solo tramcars?

Simon

Probably the GWR Railmotor which lives at Didcot railway Centre.

Here is a cab view ride where you can see the train driver using the regulator which is attached to the steam traction unit via a long rod below the carriage.




btw, a steam multiple unit train!...
For some reason this film did not play smoothly... I've no idea why but if anyone has problems please let me know and I'll uplift it again.



Simon

Not quite - multiple unit operation is operation of self-propelled railway vehicles coupled with other units of the same or similar type and being controlled from one driving cab. So this includes double-headed locomotives if both controlled by the same driver (as distinct from tandem operation where both loco are driven independently but the lead driver controls the continuous brake.
It also includes HSTs - both power cars are controlled from the leading cab.

A multiple unit trainset is a set of vehicles intended to operate in this way, and usually incapable of independent operation. It has been extended to include train sets where only one of the vehicles is actually powered but can be controlled from another - such as a power-trailer dmu, (or maybe even an autotrain) or for a single car that can be formed into an MU formation.

But yes, the railbus is not a muliple unit

.................as is done in The Taking of Pelham 1-2-3

According to the original meaning of "locomotive", it is. A "Locomotive engine" originally simply meant an engine that was self-propelled - as opposed to the stationary engines which had already been in existence for 50 years or so before they became efficient enough to move themselves. I have even seen it argued that an electric "locomotive" is no such thing because the "engine" (i.e the power station generating the electricity) is not carried on board.

An electric haulage tractor is a 'locomotive' if the electricity supply is carried on-board. Otherwise it falls into the same category as an atmospheric piston carriage or a cable grip car.
This definition of a 'locomotive engine' goes back further even than Geo. Stephenson. It was already in use when the Wylam 'Dillies' were being built.
By this definition, the East Coast electric stock, in common with most electric trains, doesn't involve a locomotive.
The HST sets, conversely, use two each. Some overpaid 'seventies advertising executive presumably chose to downplay this fact in order to make the new toy seem more 'modern' and 'exciting' than it really was.

25% increase in speed AND 100% increase in number of locomotives per train!