Beginners Ask Trains How are railroad telltales made?

How are railroad telltales made?

By Steven Otte | December 11, 2022

Used to warn trainmen of upcoming low clearance, telltales were usually made of treated rope

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A row of ropes hang from a crossbar on a telltale in front of a covered railroad bridge in a snowy landscape in Vermont
This telltale near Cambridge Junction, Vt., protected trainmen who might be walking the roof of a St. Johnsbury & Lamoille County Railroad freight train from the low clearance up ahead. Railroad telltales are made from treated rope. David P. Morgan Library collection

Q: I’m going to scratchbuild a two-track telltale for both of my tunnel entrances.  I have a couple of questions. How are railroad telltales made? What material did the railroads use? For a double track, would there be one long bar or two separate bars with the telltales on them? – Wes Barteck

A: I talked about the purpose of telltales in my “Ask MR” column of September 2017. A telltale is a trackside fixture that works like a bead curtain hanging over the track. Its purpose is to warn brakemen who might be walking on top of a car that a tunnel, overpass, signal bridge, or other low-clearance situation is coming up. If he hit the pendants, he would know to get off the roof quickly.

The dangling strands of the telltale were generally made of weather-treated rope. Wire or chain might have lasted longer, but its purpose wasn’t to hurt the train crew, after all. Most of them would cover just a single track. If two tracks led to an obstruction, a single-track telltale would be installed on each side, and if they aligned, the arms would be linked by a bar to add stability. It’s conceivable that a single telltale could be designed to cover more than one track, but such a structure wouldn’t be stable if it were supported by a single pole.

If you want to know how railroad telltales are made, turn to the prototype. The construction of trackside fixtures like this would usually be standardized, prefabricated to specifications in the railroad’s plan book. The diagram below comes from the Atchison, Topeka & Santa Fe’s engineering plan book from 1978, showing that telltales were still being constructed and used on some railroads long after roof-top brake wheels and air brakes made it unnecessary for brakemen to walk the roofs of train cars. You can’t be too safe, I guess.

A blueprint shows construction details of a Santa Fe telltale
This page from the Atchison, Topeka & Santa Fe’s 1978 engineering plan book shows the standard construction of a Santa Fe telltale. When two or more tracks were to be spanned, two posts were used, with a tie bar linking the arms above the tracks.

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