Checked content

File:Didcot disc and crossbar signal.jpg

Summary

Description
English: A Great Western Railway disc and crossbar signal at Didcot Railway Centre, England. This early form of mechanical signal was rotated to show one of two aspects to on coming trains. The disc represents 'all right' and the the crossbar represents 'stop'. On this one the extended tails on the crossbar were a later modification to identify signals protecting the down line (the one travelling away from London).
Date 24 May 2009
Source Own work
Author Geof Sheppard

Licensing

I, the copyright holder of this work, hereby publish it under the following licenses:
w:en:Creative Commons
attribution share alike		 This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
  • share alike – If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.

You may select the license of your choice.
The following pages on Schools Wikipedia link to this image (list may be incomplete):

Metadata

This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. If the file has been modified from its original state, some details may not fully reflect the modified file.
Camera manufacturer Canon
Camera model Canon PowerShot G7
Exposure time 1/160 sec (0.00625)
F-number f/8
Date and time of data generation 12:19, 24 May 2009
Lens focal length 14.783 mm
Orientation Normal
File change date and time 12:19, 24 May 2009
Y and C positioning Centered
Exif version 2.2
Date and time of digitizing 12:19, 24 May 2009
Image compression mode 3
Shutter speed 7.3125
APEX aperture 6
Exposure bias 0
Maximum land aperture 3.34375 APEX (f/3.19)
Metering mode Pattern
Flash Flash did not fire, compulsory flash suppression
Colour space sRGB
Focal plane X resolution 12,710.801393728
Focal plane Y resolution 12,725.581395349
Focal plane resolution unit inches
Sensing method One-chip colour area sensor
Custom image processing Normal process
Exposure mode Auto exposure
White balance Auto white balance
Digital zoom ratio 1
Scene capture type Standard

Did you know...?

SOS Children aims to make Wikipedia suitable for young learners. SOS Children believes education is an important part of a child's life. That's why we ensure they receive nursery care as well as high-quality primary and secondary education. When they leave school, we support the children in our care as they progress to vocational training or higher education. There are many ways to help with SOS Children.