OTMR Data Storage

[PULF]

I’m curious as to how the data storage works. Is it that each unit has a specific number of hours it can store data for and then it gets overwritten second by second once that limit is reached? Like airplanes only have a few hours but I assume OTMRs have around 28 days or something like that? I’ve always wondered because I’ve always found it odd that airplane black boxes have such a short amount of data stored and this wouldn’t be sufficient for trains?

 

[dosxuk]

Modern aircraft "black" boxes do often store significantly more data then the times discussed - because those are the minimum times that they have to record. Older models will only store what was required of them. They also have to go through a lot of other requirements, most of which serve to make it easier to read data after being destroyed and dropped to the bottom of the ocean for a month, but that in turn restrict how much data can be stored in the space available.

Pretty much all modern aircraft have a day-to-day data recorder as well as the black box, these store significantly more data, longer, but less reliably than the black box, however, there are increasing numbers of incident reports which make use of the quick access recorder (QAR), even after having to rebuild the device after an innocent.

 

[PULF]

Modern aircraft "black" boxes do often store significantly more data then the times discussed - because those are the minimum times that they have to record. Older models will only store what was required of them. They also have to go through a lot of other requirements, most of which serve to make it easier to read data after being destroyed and dropped to the bottom of the ocean for a month, but that in turn restrict how much data can be stored in the space available.

Pretty much all modern aircraft have a day-to-day data recorder as well as the black box, these store significantly more data, longer, but less reliably than the black box, however, there are increasing numbers of incident reports which make use of the quick access recorder (QAR), even after having to rebuild the device after an innocent.

Ah okay that makes sense. How do they compare with the OTMR?

 

[ZCreaser]

I haven’t really found much data on UK OTMR systems but I’ve found this for the German system if that helps?

“The standardized DSK black box allows for approximately 30,000 km of general recording data and 90 km of detailed recording data.”

 

[choochoochoo]

As an aside, do most newer traction send data continuously to fleet control/maintenance via telemetry, in which case does how long do they store that for 'off-train' ?

 

[dk1]

First OTMR was on 170s at my TOC. Rumour went round that the data was lost if taking the Battery Isolation Switch out. Amazing how many isolated the BIS if they thought they’d done something wrong.

 

[PULF]

First OTMR was on 170s at my TOC. Rumour went round that the data was lost if taking the Battery Isolation Switch out. Amazing how many isolated the BIS if they thought they’d done something wrong.

I bet! I just wonder on the average UK TOC how long a period is actually recorded. On the newer trains it’s probably a bigger period but like you say on the 170s the capacity is probably smaller and I can’t imagine it being for more than a month or so on a unit that’s used most days

 

[dk1]

I bet! I just wonder on the average UK TOC how long a period is actually recorded. On the newer trains it’s probably a bigger period but like you say on the 170s the capacity is probably smaller and I can’t imagine it being for more than a month or so on a unit that’s used most days

They were a pain to download as well as a DM had to plug an extended lead from a laptop into the roof panel in the saloon.

 

[D365]

First OTMR was on 170s at my TOC. Rumour went round that the data was lost if taking the Battery Isolation Switch out. Amazing how many isolated the BIS if they thought they’d done something wrong.

Sounds like the internal backup battery wasn’t being maintained. I’m most familiar with Arrowvale DR1000; the recorder has to be exchanged at regular intervals.

 

[PULF]

@12LDA28C Do you have any ideas on the subject?

 

[D365]

I’m not sure about the ’quantity’ of data that can be recorded on a modern data recorder, but Hasler CPMs (crash protected memory) are available in the range of gigabytes. When recording signals in a ’raw’ binary format, that’s months of capacity.

 

[dk1]

I don’t think we had clouds when the 170s were new.

 

[PULF]

I’m not sure about the ’quantity’ of data that can be recorded on a modern data recorder, but Hasler CPMs (crash protected memory) are available in the range of gigabytes. When recording signals in a ’raw’ binary format, that’s months of capacity.

Oh interesting! The Haslers are a more modern version aren’t they? The Arrowvale ones came first I believe

 

[D365]

Oh interesting! The Haslers are a more modern version aren’t they? The Arrowvale ones came first I believe

Hasler [the company] has been trading in various forms since the 1880s. Not sure when they first had a presence in UK rolling stock. Arrowvale data recorders have been around for the last 30 years, they are an entirely different product line.

 

[12LDA28C]

@12LDA28C Do you have any ideas on the subject?

Certainly the system I'm familiar with (Arrowvale) keeps data for a few weeks - I can probably get a more definitive answer later this week. Whether there is a finite period of time / distance covered before data gets overwritten I'm not 100% sure but could probably find out.

 

[PULF]

Certainly the system I'm familiar with (Arrowvale) keeps data for a few weeks - I can probably get a more definitive answer later this week. Whether there is a finite period of time / distance covered before data gets overwritten I'm not 100% sure but could probably find out.

Hi sorry for the late reply. That would be awesome if you could please!