Jump to content
Sign in to follow this  
vox

Trolleybuses

Recommended Posts

What I saw was a bus of the style seen on Sheffield roads in the 50's, but with a boom on top. Much like the one in WE's photo.

I'm sure it was a trolley bus, also that it was in Sheffield and also that it was on a hill. Maybe just not on City Road though.

Share this post


Link to post
Share on other sites

It's very possible that a trolleybus ran on City Road in the 50's. As has been mentioned already, it's possible to pick up the electricity using one boom and return it through a metal 'skate' running in one of the tracks. If the skate comes out of the track the body is unlikely to become live because, unlike a tram, any parts which can be touched by someone standing along side are fully electrically insulated. This is why trolleybuses always have plastic coated handrails and not the brass or chrome ones often associated with trams. The problem with possible electrocution comes if someone tries to put the skate back into the grooved track while the vehicle is drawing power, as the skate is the only part that can give you a shock.

Before entering service each day all trolleybuses were plugged into a tester to make sure there was no electrical leakage to the bodywork. This was part of the Board of Trade regulations for their operation and is often referred to as the Board of Trade test.

Incidentally, trams can also become electrically isolated from the rails in the case of either derailment or running over dirty track. As a tram is not insulated it can (and in Sheffield definitely has) give an unwary individual a 550v DC electric shock. One individual who this happened to was well known tram enthusiast Keith Terry. While a passenger on a farewell tour of the system the tram traversed a bit of disused track with resulted in electrical isolation. One tramwayman's trick to overmome this was to take a point iron from the car, firmly wedge the pointed end into the rail groove, then hit the other end as hard as you could onto the fender of the tram and firmly hold it there. The idea being that when the point iron is touched on the tram the current flows through it down to the track and the power is restored. Unfortunately Keith got this the wrong way around, touched the iron on the tram first and promptly found himself on the other side of the street with a new hair style!!!! A much safer method would have been to throw a bucket of water under the tram, which would also have restored the electrical continuity.

Another trolleybus fail safe is that although they normally run on around 550 - 600V DC, this is not relative to earth on properly installed trolleybus overhead. One wire is normally energised at +250V DC while the other is at -250V DC. This means that is one wire fell to the ground or the body of the bus did somehow become live when one boom came off the wires, the potential shock would only be half that from a tram. Obviously this doesn't apply where a trolleybus is operating on tram infrastructure and is another reason why skate operation is frowned upon.

Share this post


Link to post
Share on other sites
On 08/01/2010 at 21:47, jiginc said:

I have just been reading a very interesting book from the library it shows a picture that answers part of this question. It shows a Rotherham trolleybus in Haymarket dated 1912. The front wheels look like they are flanged and a skate is shown running in the rail. The book is called Sheffield Pictorial and is by David Richardson. As the picture is not attributed to a photographer I have scanned it, if this breaks copyright then I will remove it ASAP.

 

post-352-1262987169_thumb.jpg

 

jiginc

When I came across the photo' below I remembered this old topic. It appears to be the same photo' with a bit more at the bottom and is described as an electric guided bus. It is definitely in front of the Fitzalan Chambers on the Haymarket.

"This guided bus uses a sprung loaded down force to locate the jockey wheel in the tram tracks in Rotherham. Power comes from the tram overhead with drive to the rear wheels by chains. The chassis is by David Brown and two 20hp Siemens motors are used .

EDIT -- I have just noticed that the Rotherham Corporation Transport 1903-1974 .pdf available at the link below has the same picture with the following information  -----  "No. 39 - one of Rotherham’s first trolleybuses delivered in 1912. It was a Railless with Milnes Voss 29-seat bodywork, later registered ET1923 and re-numbered T2. (LTHL collection)."

http://www.lthlibrary.org.uk/library/PDF-041-1.pdf

electric_guided_bus.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×