![](https://coimages.sciencemuseumgroup.org.uk/423/802/large_thumbnail_1994_8782__0004_.jpg)
Telegraph block instrument (permissive)
![Telegraph block instrument (permissive)](https://coimages.sciencemuseumgroup.org.uk/534/201/small_thumbnail_smg00358072.jpg)
![Telegraph block instrument; BR](https://coimages.sciencemuseumgroup.org.uk/423/193/small_thumbnail_1994_7266__0008_.jpg)
![Telegraph block instrument; BR](https://coimages.sciencemuseumgroup.org.uk/423/191/small_thumbnail_1994_7266__0004_.jpg)
![Telegraph block instrument; BR](https://coimages.sciencemuseumgroup.org.uk/423/192/small_thumbnail_1994_7266__0006_.jpg)
![Telegraph block instrument; BR](https://coimages.sciencemuseumgroup.org.uk/423/190/small_thumbnail_1994_7266__0002_.jpg)
Telegraph block instrument; BR. Standard modularised 2-needle (2-9)permissive (Down/Up Platform 7A/B; dynataped) 3-position type with a white black-arrowed bakelite wedge as commutator, tapper/blockbell unit underneath, and a plastic case traffolyte-plated "CHESTER No 3A". Known as a 'Penguin'.