Train engine bouncing

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Kwantumnaut
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Joined: Thu Nov 05, 2020 7:33 pm

Train engine bouncing

Unread post by Kwantumnaut »

Hey y'all. So today while out watching a couple trains operating at a trainyard nearby I noticed one of them, (or rather one that was just 2 engines and no cars) seemed like most of the front half of the leading engine body was bouncing up and down as it went by.

I didn't notice the wheels leaving the track at all, just more like the front half of the body. I've never seen any others do this at this same spot, so assuming it wasn't the track, I'm just wondering what might've caused it with the engine then.

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SD80MAC
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Re: Train engine bouncing

Unread post by SD80MAC »

Maybe the shocks are going bad on the front of the locomotive. Also, if you ever see the wheels leaving the track, run (that doesn't happen unless a derailment is in progress, locomotives are far too heavy for the wheels to leave the track just from a low joint in the track or shock absorbers that need replacement).
"Remember, 4 mph is a couple, 5's a collision!"
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Kwantumnaut
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Joined: Thu Nov 05, 2020 7:33 pm

Re: Train engine bouncing

Unread post by Kwantumnaut »

That was my best and about my only guess was maybe something to do with the shocks. It wasn't any severe, extreme like 5ft up and down bouncing, just more of a noticeable bobbing was all.

PatAzo
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Re: Train engine bouncing

Unread post by PatAzo »

A more detailed explanation of the role of springs and dampeners in a truck. https://www.wheel-rail-seminars.com/arc ... ension.pdf

You said two locomotives and no cars. I don't know about newer truck designs but many older locomotives were restricted to 30MPH when operated light engine. My understanding is light engines could begin hunting side to side without a load on the rear drawbar.

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DaveO
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Re: Train engine bouncing

Unread post by DaveO »

Was it bouncing like this :?:
https://youtu.be/AtQvekZ-nTk
:shock:

The person that made this video, Rod Williams, died 5 or so years ago but his videos live on.

PatAzo
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Re: Train engine bouncing

Unread post by PatAzo »

Or like this?


Kwantumnaut
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Re: Train engine bouncing

Unread post by Kwantumnaut »

PatAzo wrote:
Sun Jan 03, 2021 8:46 pm
Or like this?

Hey yes actually that looks quite exactly like what it was doing

PatAzo
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Re: Train engine bouncing

Unread post by PatAzo »

SD80MAC speculated worn shocks. Watch the CSX train go through the crossing a few times from about the 1:00 mark. The lead unit has some vertical movement going on before it hits the low spot at the crossing. The watch the second unit come through the crossing. It goes out of view quickly but appears to dampen out much quicker than the lead unit. Bad spot in the track coupled with worn dampeners. The energy stored in the springs is transmitted back into the locomotive.

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